238 AGRICULTURAL EXPERIMENT STATION. 



Description of the Larva. 



The larva is figured on plate fig. 70, with details of structure. 

 When full grown (fig. 70, i ) it is 7-9 mm., = .28^.36 of an inch, 

 in length, excluding the anal siphon, and yellowish grey in color. 

 The young larvae are light colored, almost white, but become 

 darker as they grow larger. The head is broader than long, and 

 lighter in color than the rest of the body ; the maculation on the 

 vertex is very constant, never diverging from the type shown 

 on plate fig. 60, 1-3, and each separate mark has well defined 

 edges. Rarely, there is a blotch near the front, on top of the 

 head, which is diffused and sometimes clouds the whole head, 

 partly obscuring the maculation and giving- it a darker or even 

 black appearance. There are four tufts, consisting each of three 

 or four hairs, one pair a little in front of the other, and a larger 

 tuft at the base of each antenna. The antenna (fig. 70, 3) is 

 short, with a single, very perceptible curve, dark brown, paler 

 at the base and sparsely set with short, stout spines. The tuft 

 is composed of eight or ten hairs and is situated on the shaft, a 

 little below the middle. At the apex is a long and short spine, 

 two bristles and a small joint articulated to the main segment. 

 The eyes are best seen from the side, and are large, crescent 

 shaped, widest below, becoming acute at the vertex. There are 

 two sets of hairs composing the rotary mouth brushes, a very 

 heavily pectinated set situated in the center and a simple set 

 occupying the lateral portions. The mentum (fig. 70, 6) is tri- 

 angular, with nine or ten teeth on each side of the apex, the 

 sides well rounded and the base flat. There is some variation, 

 the sides in some specimens being only slightly curved, but this 

 is rare. The mandible (fig. 70, 4) is normal and set with a 

 few very small spines on the dorsal surface of the base. The 

 maxillary palpus (fig. 70, 5) has a large tuft of moderately long 

 hairs and the body is clothed with hairs arranged in roA\'s and 

 patches. The thorax is rounded, with scarcely any angulations 

 in the full grown larva; in the immature larva it is more trans- 

 verse and distinctly angulated. Lateral hairs issue from a num- 

 ber of tubercles at six points, and there are two tufts of small 

 fine hairs at the anterior margin. Abdominal segments from 

 one to seven are oblong or sub-quadrate, and each has a tuft of 

 lateral hairs, becoming shorter and fewer posteriorly. The eighth 

 segment has lateral patches of scales (fig. 70, 8), from thirty- 

 five to forty in each patch, arranged as shown in fig. 7. The 

 scales are fewer in number in the young larA^se but usually of the 

 same shape. The anal siphon (fig. 70, 7) is two and one-half 



