﻿OF CORYDALUS CORNUTUS. 165 



4. Comparison of the Changes which take place in (he three Stages. — The compara- 

 tively wide oesophagus and proventriculus of the larva, which extend as far back as the 

 third abdominal segment, we find contracted in the pupa and shortened to the posterior 

 part of the mesothorax ; the proventriculus with its apparatus of stomachal teeth has 

 disappeared, and a small crop exists in its place, whilst in the imago we find the oesoph- 

 agus again lengthened, still contracted at its commencement, but gradually dilating as 

 it passes backwards, until it finally forms a capacious proventriculus, which, with the 

 oesophagus, extends as far back as the fifth abdominal segment. The proventriculus of 

 the imago has no return of the teeth of the larva, is thin in its walls, and has a small 

 ccscum posteriorly, which is apparently the remains of the crop of the pupa. The col- 

 umnar ventriculus of the larva, with its short anterior coeca, we find becoming converted 

 into the elongated coeca of a newly developed fusiform ventriculus of the pupa ; and in 

 the imago we find the ventriculus contracted and the coeca somewhat changed in form. 

 The large intestine shows but little change in passing from the larva to the pupa, but in 

 the imago we find a ccecum, and numerous glands formed upon it. Within the posterior 

 abdominal segment on the ventral aspect of the terminal portion of the large intestine, in 

 all the stages, there exists an irregularly ovoidal sac, which contains a greenish viscid 

 fluid. The exit of this sac, which is probably urinary, is at the edge of the anal orifice. 



II. Generative Apparatus. 



In the larva the organs of reproduction exist in a very rudimentary state. The 

 ovaries and testes have the same appearance, being elongated-ellipsoidal in form, com- 

 posed of transverse fibres or indistinct tubules joining a common tube, and containing 

 round bodies or organic cellules undistinguishable in any of the individuals examined. 

 They are situated one upon each side of the small intestine, and from their posterior part 

 proceeds a tube which joins its fellow beneath the urinary sac. 



In the pupa the apparatus has become much more developed. The testes of the 

 male have become much increased in size, and elongated as far forwards as the meta- 

 thorax. The tubuli seminiferi are short tubes transversely situated, and all converging 

 to the vas deferens. They contain spermatozoa in various stages of development. 



The ovary of the female has also increased in length, though not to such an extent as 

 the testicle, but has gained upon the latter in breadth from the lengthening of the 

 ovigerous tubules. The ovarian tubules contain numerous ova in an immature condition, 

 and sufficiently transparent within the tubuli to render their vitellus visible. In the male 

 imago the testes have reached their highest point of development. They do not differ 

 much in appearance from those of the pupa, excepting that in the individual particularly 

 examined they were rather shorter. The tubuli appear more engorged, and contain per- 



