512 Mr. C. L. Witliycombe's Notes on 



Family I. OSMYLIDAE. 



We liave one British species, Osmylus chri/sops L. The 

 structural characters of this are typical of the family. 

 Larva amphibious. 



Osmylus chrysops Linnaeus. 



Wing expanse 44-47 mm. Colour dark fuscous, Avings hyaline 

 with blackish-brown spots. 



The head is of an orange colour in life, with three ocelli on the 

 vertex, in addition to the usual pair of compound eyes. Thorax 

 and abdomen dark brown, the latter with one more or less distinct 

 white spot on either side of each segment. Wings ample, densely 

 reticulate. In fore-wings the humeral cross-vein is not markedly 

 recurrent. Costal field broad. Subcosta and radius are confluent 

 in region of pterostigma. But one sector to the radius. 



This large and beautiful insect cannot be mistaken for 

 any other of the British Neuroptera. It is slow on the 

 wing, and rather reminds one of an ant-lion in appearance. 

 Its favourite haunts are streamsides in wooded districts. 

 Here, within a radius of ten to twenty yards, a few dozen 

 specimens may occur and often no more for miles. This 

 local occurrence is no doubt correlated with the feeble 

 flight and sluggish habits of the species. Time of appear- 

 ance from May to Jul}^ 



Two or three days after pairing, eggs are laid (Plate 

 XXXVIII, fig. 6). These are firmly attached by their flat 

 sides to a surface, not on moss, etc. The eggs are placed 

 closely in contact, side by side, in a straight or slightly 

 curved row of from two to twelve in number. It is not 

 often that eggs are laid singly. The egg is TS mm. in 

 length, of long oval shape but rather flattened. The chorion 

 is reticulated, and there is a white micropylar knob. At the 

 micropylar pole the egg is somewhat drawn out, giving the 

 knob a slight pedicel ; the opposite pole of the egg is rounded. 

 The colour is at first whitish, slightly yellow. In five or six 

 days it has darkened to brown, and later, especially just 

 before hatching, the colour is ashen. After an incubation 

 period of twenty-two days, with an average temperature of 

 69° or 70° F., the larva escapes by a slit in the eggshell 

 extending from just behind the micropylar knob on the upper 



