wavenovel Chapter 964: Something is wrong with the bug
Chapter 964: Something is wrong with the bug
Chapter 964 The th Bug Is Not Right
It is relatively easy to distinguish the third instar larvae, because this is the last step for the larvae to become adults. Its body has become very large and its appearance can be seen clearly. Then it can pupate and become a fly.
So, sometimes the creature that emerges from the cocoon may not be a butterfly, it may be a moth or even a fly.
Under Jiang Yuan's guidance, Wan Baoming quickly became familiar with several common third-instar larvae.
When it comes to biology, you learn it very quickly in practice. When I read books and looked at pictures in school, I always couldn't remember clearly, such as the eighth and ninth abdominal segments. But if you see the real thing, see it several times and compare it several times, your mind will remember it very quickly.
For example, the most common maggots in dry toilets are cylindrical and slightly flat, with a pointed tail. Their surface is slightly transparent and slightly yellow. They are the big-headed golden fly of the Calliphoridae family, with the scientific name (Chrysomyia megacephala Fabricius).
The big-headed golden fly is also the most common necrophile fly, especially in places with many dry toilets. Whenever a corpse appears, a big-headed golden fly will fly over and lay eggs, thus becoming a good helper for forensic doctors.
The big-headed golden fly is not only helpful to forensic doctors, but also to my country's traditional Chinese medicine industry. Traditional Chinese medicine uses "grain worms" as medicine, mainly for "strengthening the spleen and eliminating accumulation; clearing away heat and eliminating malnutrition". It should be noted here that some herbal medicine merchants now also use the larvae of other flies as medicine, because ordinary people do not know the business, and it is easy to be inferior to good ones. Especially at the moment when medicines are directly ground, there is no place to complain even if the crushed grain worms are not the same as the ones advertised.
Therefore, when you really need to use the "grain bugs", if you can't catch them yourself and don't want to be deceived, you can first observe and learn in the dry toilet. There are only a few provinces in China that lack the distribution of big-headed golden flies, mainly in Heilongjiang, Jilin, Qinghai, Xi'an and Xinjiang. It is easy to find them in other places.
For people in these places, if they really don't know how to distinguish them, they can compare them with the calves of ballet dancers. The shapes and appearances are basically the same, which shows that beauty and ugliness in the world do have something in common.
With Wan Baoming's help, Jiang Yuan quickly started to screen eggs and pupae.
Flies undergo complete metamorphosis - they develop from eggs to larvae, from larvae to pupae, and from pupae to adults, each time undergoing complete metamorphosis, meaning they completely change into a different appearance.
This gives each form of fly a distinctive appearance, and identification is easy for those who know how.
Despite this, Wan Baoming's eyes widened when Jiang Yuan began to classify the fly eggs.
"Can you really tell who laid the eggs just by looking at it?" Wan Baoming had seen and eaten them before... or to put it another way, he had worked with the big guys in entomology, but he had never seen anything like this.
If a normal boss wants to do such a detailed classification, when classifying to specific species, he actually has to check reference books, such as "Fauna Sinica", "Economic Insects of China", "Keywords of Common Flies in China", etc.
This is just like experts in writing also need "Shuowen Jiezi" and "Kangxi Dictionary".
Jiang Yuan didn't need to explain too much to Wan Baoming. He just smiled and said, "You can't tell it just by looking at it once. Sometimes you have to look at it a few more times..."
Mu Zhiyang couldn't help but look up at Jiang Yuan: "Captain Jiang, when you look at the fly eggs, it's a bit humorous."
Jiang Yuan smiled and said without even looking up, "Put on a pair of gloves and help me clear out the insects and eggs in these bottles. Place them on the glass plate so I can identify them later."
Mu Zhiyang said "Oh", put on gloves, took a bottle specified by Jiang Yuan, opened the cork, and smelled a strong stench.
The stench was quickly sucked away by the ventilation equipment above his head, leaving Maki Zhiyang only able to inhale enough.
On-site investigators don't know how to distinguish the types of these insects. In the final analysis, they just scoop them out with a spoon, poison them, put them in bottles and bring them back. In addition to insects and insect eggs, many bottles inevitably contain some dead water.
I didn't notice it at the time because the stronger smell covered it up, but when I returned to the laboratory and smelled it again, I was very addicted.
Before long, the black leather test bench was filled with the bodies of various maggots. Millimeter-sized eggs were also placed in disposable plastic culture dishes, neatly arranged one by one.
Mu Zhiyang then helped write labels and stuck them on one by one.
In addition, there are more insects that do not belong to flies and their larvae and eggs.
These are all tedious and detailed tasks, but only by doing them carefully can we get to the stage of determining the time of death.
In fact, the main work is to identify the types of eggs, larvae, pupae and adults. The rest of the work, in theory, is not much, as long as you follow the steps...
"There's something wrong with these bugs." Jiang Yuan stopped after watching them.
"There's something wrong with the bug?" Wan Baoming didn't realize what was going on for a moment.
Jiang Yuan said "hmm" and then looked at the records he made and thought.
When the technicians in the room heard the conversation between the two, they all stopped subconsciously.
Many operations are lossy operations. If you are not in a hurry, it is always a good idea to wait.
Jiang Yuan sat down by himself, studied it with a pen, then looked at Wan Baoming and said, "Now that I look at it, I feel that what I see are not flies of the same lineage, not one group, nor two groups..."
Generally speaking, after a corpse appears, nearby flies will come to lay eggs at the fastest speed, and this fastest speed is often measured in seconds. In addition, the generation of flies is relatively clear, hatching every few days and growing up every few days. It cannot be said to be accurate, but there is a certain pattern.
Forensic entomology determines the time of death based on the reproduction and growth of insects.
For example, it takes about 20 days for a worm to grow to the third instar, so the dead worm has been dead for about 20 days. If the dead worm has been dead for longer, it can be a worm of the second or third generation, so just add up the time and calculate it.
Here is a little-known fact: the adult flies usually start to reproduce a few hours after they emerge from their cocoons. This does not delay the forensic doctor's time calculations at all.
However... the feeling that this group of insects gave Jiang Yuan was not so clear.
Wan Baoming asked: "The body we found was at the second scene. Did the two scenes interfere with the time?"
"It is definitely an interference. The problem is, judging from the current situation of the flies..." Jiang Yuan said here, tapped the notebook, and said: "My judgment is that the scene we found is no longer the second scene, but the third scene."
"Ah?" Wan Baoming was stunned: "The third scene? The body parts were moved twice? Why?"
(End of this chapter)