98 INTERNAL ANATOMY OF INSECTS. 



in the larva, though it does not circulate by means of a 

 vascular system. The chyle that is produced in the in- 

 testines of animals from the food, is that fluid substance 

 from which their blood is formed : in insects it is not ab- 

 sorbed by the lacteals, but transpires through the pores 

 of the intestinal canal into the general cavity of the body, 

 where, being exposed to the influence of the oxygen in 

 the air-vessels, it becomes, though retaining its colour, 

 a different fluid from what it was before, and analogous 

 to blood in its use and office a ; only that in these animals, 

 as Cuvier has observed, at least in their perfect state, the 

 blood, for want of a circulating system, not being able 

 to seek the air, the air goes to seek the blood b . The 

 dispersion of this fluid appears to be universal, so that 

 all the parts and organs contain it in a greater or less 

 degree c . In many insects, if you break only an antenna 

 or a leg, a drop of fluid flows out at the wound. In larvae, 

 the fluid which bathes d , or visits, all the internal parts and 

 organs is not only sufficient for their nutriment, but a 

 large quantity of seemingly superfluous blood remains that 

 is not wanted for this purpose. This is expended in 

 the production of the caul or epiploon (Corps graisseux 



51 Herold Schmetterl. 24. b Anat. Comp. iv. 165. 



* Marcel de Serres (p. 67.) speaks of this fluid as being, after it 

 has transuded through the intestinal canal, a fluid in repose, which 

 seems to indicate that it is perfectly stagnant ; but when we consider 

 that it is not only incessantly entering the body and making its way 

 to every part, but is also, by means of the various secretory organs, 

 constantly converted into new products, and so going out again in 

 many cases, it will appear evident that it cannot be considered as a 

 stagnant fluid, since there must be a constant though probably slow 

 motion towards the points of absorption or imbibition. 



d Dr. Kidd (Philos. Trans. 1825. 236.) did not find the abdominal 

 viscera of the mole-cricket thus circumstanced, nor more lubricated 

 than the intestines of the higher animals. 



