THE LARCH LAPPET LARVA : ITS FOURTH STAGE. 93 



Fourth Larval Stage. 



The third molting, as in the second, commenced seven days after 

 the earliest of tlie preceding molt, on May 5th, when but about two- 

 thirds of the larvae had undergone their second change. Of the dura- 

 tion of this molt, or of the dates of molting, no record was kept. 



The hirvie show the following dorsal markings, liestingon segments 

 3 and 4, a sublenticular yellow spot, bordered with velvety black, and 

 bisected by a narrow brown mesial line; on segment 7, a yellow spot of 

 Avhich the anterior portion is split by a wedge-shaped brown projection 

 — its greatest breadth between the tubercles, extending on segment 8 

 and terminating in a point between the tubercles of this segment. In 

 some examples, a somewhat similar shaped spot of paler yellow is seen 

 on segment 9, extending a little on segment 10. The yellow lateral 

 markings which in the former stage formed an interrupted line below 

 the tubercles are reduced to a series of indistinct ochreous spots at the 

 base of each tubercle. The cylindrical tubercles on segment 3 are 

 quite projecting and rounded at the tip ; the subdorsal tubercles pre- 

 sent the following ratio of size in the order of their occurrence : 1, 2, 

 7, 9, 6, 10, 5, 4, 12, 11, 8, 3 (that on segment 1 being the largest, and 

 on segment 9 the smallest). The subjoint of segment 12 has two ele- 

 vated black points. The barbed gray hairs composing the fringe have 

 some barbless ones mingled with them. The legs are luteous, marked 

 with bhick exteriorly, and are nearly hidden by the overlapping fringe. 

 Beneath, on segment 2, are three small mesial spots ; on segment 

 3 ai"e two sj^ots ; on the following segments, an obscure larger one 

 mesially on each ring ; the body ventrally is marked with crinkled 

 Imes. 



Previous to the fourth molting, the larvae measure 1.2 inch. Tlie 

 8tli tubercle in the subdorsal row is conical; the 11th has 

 a broad base, extending anteriorly to the incisure. Upon 

 the first five segments the barbed hairs of the fringe are 

 more numerous. 



This stage, as was ascertained later, was the last larval 

 stage of a portion of the brood ; a part entered upon a 

 Fio. i9.-Head fifth stage. The head of these, taken from east head- 



Of TOLTPE LARI- ..!•/> ,1 !.• /I 1 , ■ T 



CIS, female, in cases at their lourth molting (enlarged to six diameters 

 fourth stage, ^s the preceding ones), is represented in Fig. 19. 



Mature Larva. 



The largest attained a length of nearly one inch and a half. The 

 color is a dull brown, resembling that of the bark of the pine twig. 

 The head is covered with black hairs superiorly, and with gray hairss 



