the Biology of some British Neuroptera. 519 



silk glands, in the last instar. Hagen gives seven as the 

 number of Malpighian tubes, but I have never seen this 

 number in Osmylus. 



The adult gut is of usual pattern, with a large food 

 reservoir (Plate XXXVIII, fig. 9). The six silk secreting 

 tubes are still slightly attached distally to the hind-gut. As 

 in the larva, they first run forward from their point of origin 

 and are then recurrent to where the ends are attached to 

 the hind-gut. The first portion of the Malpighian tubes is 

 colourless, but the recurrent portion, approximately coin- 

 ciding with the previous silk secreting part of the larva, is 

 pigmented with dark brown. This also occurs in Sisyra. 



In the male the testes are united and covered bv a 

 common yellow scrotum (Plate XXXVIII, fig. 10). Thislies 

 under tergites 7 and 8, mainly the latter. Posteriorly, two 

 distinct vasa efferentia run back. These are yellov/ish until 

 they become convoluted into a small knot. Thence they 

 are dark crimson-brown in colour and pass ventrally one on 

 each side of the hind-gut to enter the vesiculae seminales 

 from below. Vesiculae seminales are large whitish struc- 

 tures, yellow centrally, with two anterior recurrent lobes 

 and on each side with a small, somewhat coiled accessory 

 diverticulum. The ductus ejaculatorius runs ofl from 

 below, and its extremity can be seen externally as a small 

 white papilla between the claspers. It is not a true penis. 

 How such a large spermatophorc can pass through such a 

 small duct I cannot say. 



The anatomy of the female does not call for special 

 comment in the present paper. 



Family II. SISYRIDAE. 



Small insects of dark colour. The genus Sisyra is typical 

 of the family. Larva aquatic, feeding within or upon 

 freshwater sponges. 



There are three British species, Sisyra fuscata, S. termi- 

 nalis, and S. clalei. I have seen all stages of the first two 

 species, and they are hardly distinguishable. The following 

 account refers mainly, however, to Sisyra fuscata, which is 

 the commoner of the two. 



Sisyra fuscata Fabricius and S. terminalis Curtis. 

 Wing expanse 12-14 mm. Colour wlioUy dark fuscous. Wings 

 unmarked. There are no ocelli. In the fore-wings there is no 



