294 Mr. Clark'/ Obfervations on the Genus Oeflrus. 



which extends from one extremity to the other, and ferves the 

 double purpofe of ftomach and interline. The inteflinal canal ot 

 the larva of the CE. Equi is feen reprefented at fig. 26. 



The apparatus of air tubes in this larva is very lingular, and is 

 reprefented fomewhat magnified at fig. 25. In this fpecies there 

 are only two principal trunks of thefe air vefTels, which are con- 

 nected near their origin by a lateral trunk. From thefe, branches 

 are feen pafling off in every direction through the fubftance of the 

 in feci:, fome of them to the interline, others to the ikin, and a greater 

 number appear to terminate by anaftomofing with each other. As 

 thefe air vefTels form a much greater part of the flructure of the 

 larva of the (E. Equi, it will be more proper to fufpend our obfer- 

 vations on them till we come to the defcription of that fpecies. 



The larva having arrived at its full growth, effects its efcape from 

 the abfcefs, by preffmg againfl the external opening, which occafions 

 its enlargement by the points prefTed upon being gradually ab- 

 sorbed. When the opening has thus obtained the fize of a fmall 

 pea, the larva writhes itfelf through, and falls from the back of the 

 .animal to the ground,, and^feeking a convenient retreat, becomes a 

 chryfalis. 



With confiderable difficulty I obtained three chryjalides of this 

 infect ; one of which is reprefented at fig. 3. 



Theie larva never change or throw off their fkin, the fame 

 ferving them through their whole growth ; and it at length alfo 

 ferves to form the {"hell of the chryfalis. After leaving the abfcefs, 

 and previous to their becoming a chry falls, they contract themfelves 

 into much lefs fpace, and affume a different figure. See fig. 2. The 

 fack which enclofes the larva beneath the (kin, is formed of a tough, 

 thick membrane, and rough on the in fide; and the pus fecreted 

 by it, is moftly of a yellow colour. After the exit of the cater- 

 1 pillar, 



