the Biology of some Brilish Neuroptem. 527 



Sympherobius pygmaeus Ranibur. 



Wing expanse 8-10 min. Our smallest British Hemerobiid. 

 The wings are dark brown in colour, but lighter than those of S. 

 ehgans. There are two radial sectors in the fore-wings. Veins 

 dark brown with whitish interruptions. At base of fore-wings, veins 

 are paler in colour. Hind-wings wholly pale. The small size, 

 but two radial sectors, and white dotted veins, render this quite 

 distinct from all other species of British Hemerobiidae. 



As far as my observation goes, this species is confined 

 to oaks. As a rule it is decidedl}^ uncommon, but occasion- 

 ally appears, locally, in abundance. The insects may be 

 beaten from oak, from June until Septem-ber, although 

 there does not appear to be more than a single brood. 



Eggs are laid on oak leaves in similar positions to those 

 chosen by the Coniopterygidae, i.e., at the extreme margin 

 of the leaf, on the under surface. At other times they may 

 be found alongside the main veins, on the underside. 

 Rarely two or three eggs are deposited in one leaf margin, 

 but generally they are placed singly. The egg is -42 mm. 

 long, oval, with bluntly rounded ends and a very small, 

 inconspicuous micropylar knob. It is of general Hemero- 

 biid pattern, with a granular pitted chorion, the ends of 

 the egg are, how^ever, more rounded, and the micropylar 

 knob is relatively smaller than in Ilemerobius. At first 

 the colour is white and translucent, later darkening slightly 

 to greyish. Hatching takes place in ten to twelve days, 

 and just before this happens the brown segmentation and 

 eyes of the embryo are visible from without. 



The newly hatched larva is apj^roximately -6 mm. long, 

 pale brown in colour, with a blackish head. It much 

 resembles a larva of Heinerobius and moves with a rapid 

 side-to-side motion of the head. The main differ- 

 ence from a Henterobius larva now is in the distinct 

 segmentation of the antennae into three joints ; Heinerobius 

 having the second and third joints similar, appearing con- 

 tinuous as one. Also the palpi are relatively thicker, and 

 swollen distally. The second-instar larva is very similar 

 to that of the third instar. 



Description of Third-instar Larva. (Plate XL, fig. 1.) 

 Length when full fed about 4-5 mm. Body smooth, fusiform, 

 and relatively slightly broader than that of Hemerobins. Colour 

 creamy-white with dark brown latero-dorsal longitudinal bands. 



