﻿166 INTERNAL ANATOMY 



fectlj formed spermatozoa. The vasa deferentia converge and join beneath the urinary 

 sac to form a short ductus ejaculatorius, which latter terminates by an orifice at the ex- 

 tremity of an insignificant papilla, the only trace of a penis, existing upon the ventral 

 surface in the interspace between the penultimate and last abdominal segment. 



Attached to the last abdominal segment are four articulated appendages, which ap- 

 pear to have for their purpose the retaining hold of the female in coitu. In the female 

 the ovaries are large, about two thirds the length of the testicle of the male, but three 

 times as broad, and thicker. Each ovary consists of numerous ovigerous tubes, trans- 

 versely arranged, commencing in fine points and gradually dilating to their termination 

 in the oviduct. The tubes are held together, as well as the ovary in its position, by the 

 numerous ramified trachea?. Each ovarian tube contains ova in various stages of develop- 

 ment, from a mere point at their commencement to two lines in length at their termina- 

 tion. There are generally from four to five ova matured, or nearly so, in each tube. 



The mature ovum is about two lines in length and elongated-oval in shape. 



The oviduct at its commencement forms the base of the ovigerous tubes, the oppo- 

 site wall to the openings of which is thin and transparent. It becomes contracted at 

 the posterior part of the ovary into a tube, which, passing backwards a few lines, joins 

 its fellow to form a common tube, about a line in length, terminating in the vagina. 



The vagina lies beneath the urinary sac, within the penultimate abdominal segment. 

 It is a short, rounded receptacle, ending in a perforated papilla, rather longer than that 

 of the male, between the ventral plates of the last and penultimate abdominal segments. 

 From the foregoing description of the genitalia it is seen there is no true intromittent 

 organ in the male, and almost no receptacle for such an organ in the female. I think it 

 probable that the papilla, terminating the generative organs in both sexes, are applied to- 

 gether in coitu, whilst the female is retained in position by the abdominal appendages or 

 claspers of the male. 



III. Nervous System. 



The number of centres or ganglia, in correspondence with the number of free mov- 

 able segments of the body, remains the same throughout the three stages of existence. 

 The ganglia, as is usually the case in the Neuroptera, are well developed or large in 

 size, and, in correspondence with the activity of the animal, give off numerous nerves. 



1. Particular Description in the Imago. — The cerebrum, with its lateral productions, 

 the optic nerves, forms a cylinder extending between the eyes and presenting four swell- 

 ings. From its upper surface pass off three nerves to the simple eyes ; anteriorly, the 

 antennal nerves and the arched commissures to the frontal ganglion ; and interiorly, the 

 cerebro-cerebellar commissures. 



