'214 BRITISH LEPIDOPTERA. 



recent visit of larvae even when the latter are not visible as they are soon 

 covered with sand. They run over the sand with great ease in search 

 of a fresh plant and are very active between 3 p.m. and 6 p.m. They 

 are most abundant at St. Pol de Leon during the first week of September 

 400 being collected in three days. Curtis states (on the authority 

 of Raddon) that the young larvae are not easily discoverable, but that, 

 when large, they are so conspicuous that their numbers are reduced 

 by marine birds which feed upon them ; they can also, at this stage, 

 be traced by their frass and are sometimes to be seen- resting at 

 the extremity of a culm of a small rush, and, at Braunton Burrows, 

 used to be fullgrown about the middle of September. In the Channel 

 Isles near St. Helier, the larvae were formerly collected in August (Batho), 

 whilst at St. Poldu, Harrison reports that larvae were abundant at end of 

 July (28th-29th), 1397, and that pupation commenced by August 4th, 

 whilst John found larvae in the Forest of Fontainebleau, August ist-4th, 

 1872, which, being sent to Buckler, pupated between August 9th-i8th. 

 Chaumette observes (ZooL, ix., p. 3158) that the larvae, known to 

 Swiss children as " Chenilles de Tithymali," are usually more or less 

 gregarious, that as many as 150-200 may be found in one spot, 

 often fewer, but rarely solitary ; he further notes that, in feeding, they 

 gnaw the lower leaves of the spurge from apex to base, and eat very 

 rapidly. We have repeatedly found the larvae in Switzerland, 

 Dauphiny and Piedmont, and have also noticed this gregarious 

 tendency, and, large and conspicuous as these larvae are when looked 

 for, it is easier to walk over them than see them at a casual glance. 

 Their lazy habits are beyond belief, and their powers of eating 

 extraordinary. The larva will stand on a stem of the foodplant, 

 eat the leaves one by one, commencing at the top, as well as the 

 stem itself, only stepping backward as the stem becomes shorter, 

 and at once reach forward to the nearest leaf. Some in confine- 

 ment did not move during the night, but were found in the same 

 position as they had taken up the previous night. Between Evolena 

 and Villar they were exceedingly abundant in early August, 

 1899, the smaller ones clinging to, the larger stretched across, 

 the foodplant in the morning sun, and again their general 

 similarity to their surroundings was noticeable, due, it would 

 appear, entirely to the effect of light and shade on the hues of the 

 larva, producing a general resemblance to the colour of the leaves 

 and blossoms of the spurge on which they rested ; there was no 

 special part of the plant to which the larvae bore a special resem- 

 blance, and a larva, practically invisible in one position, often 

 became quite conspicuous from another standpoint. Merrifield 

 observes that, in the Vals-Platz, they are conspicuous enough, 

 lying across their foodplant or sometimes on a grass bent arising 

 out of it, and are very sluggish, except, occasionally, when crawling 

 from one patch of their foodplant, nearly eaten down, to another. 

 After commenting on the conspicuous spots of these larvae, the 

 same observer details (Ent. Ree., xii., p. 320) an experiment tending 

 to prove their inedibility as far, at least, as fowls are concerned. 

 Weismann, on the other hand (Shi dies in the Theory of Descent), 

 states that a lizard that would not eat a larva of Celerio gallii, at 

 once attacked and swallowed a large larva of Hyles euphorbiae. 

 Mathew states that, in Malta, the larvae are much attacked by cen- 



