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II. On the Life Hidory of Drilus flavescens, Rossi. By 

 Lionel R. Chawshay, M.A. Oxon. Communicated 

 by Charles Owen Waterhouse, F.E.S. 



[Read November .'itli, 1902.] 



Plates I and II. 



The following notes on Drilus flavescens are collected 

 from observations made during the past three years. In 

 July 1900 I first found the larva on the Downs, near 

 Seaford, Sussex, and in this year reared five larvaj (all 

 females), four of them emerging in the following spring, 

 and the fifth continuing its growth for another summer. 

 In 1901 I collected several more larvae from the same 

 locality, and from these I obtained in the spring of the 

 present year (1902) a single male, and a few females, the 

 remainder reappeariiig as larvae. 



In spots where snails — ■Helicella itala and HelieeUa 

 virgata especially — cover the ground in immense numbers, 

 it is not surprising that tlie larva thrives on its food- 

 supply, and it may often be seen during the summer 

 months, running hastily over the ground in search of food. 

 Before passing to its life history, the form of the larva 

 deserves some notice. 



The larva, which is narrowed in front and much widened 

 behind, has the upper surface of the abdomen rather 

 thickly covered with coarse hairs of a bright burnt-sienna 

 colour, springing chiefly from four longitudinal rows of 

 fleshy processes, the processes increasing in length towards 

 the posterior. The head is reddish-brown, flat above, 

 with strong sharp mandibles, curving upwards and crossing 

 one another above the labrum ; the eyes consist of a single 

 ocellus on either side. The antennae (Plate I, fig. 1 ; 

 Plate II, fig. 1) are two-jointed with a supplement to the 

 second joint, and can be partially extended or withdrawn 

 by the larva by means of a collapsible membranous tube 

 which carries the first joint, the latter being thrust forward 

 or partially withdiawn within the tube by a muscle which 

 passes up the centre of it to the apex of the first joint. 

 The second joint is somewhat flattened and bears at its 



TRANS. ENT. SOC. LOND. 1903 — PART L (aPRIL; 



