4 BULLETIN 843, U. S. DEPARTMENT OF AGRICULTURE. 



at the apex. The surface is strongly sculptured. The length of the 

 egg is 1.25 mm. ; the width 0.6 mm. 



The eggs are deposited on end on the lower surface of the bean 

 leaves (PL IV, fig. 1) in irregular masses, varying from half a dozen 

 to about 75, with an average of between 40 and 50. (See fig. 1, d.) 



THE LARVA. 



The larva is yellow and the body is armed with long, formidable, 

 strongly branched spines, darker at the tips. When full grown these 

 spines, although somewhat irregular, are arranged in rows both 

 longitudinally and transversely, as shown in the accompanjdng illus- 

 tration (fig. 1, a). The head is moderately prominent, as are the 

 mandibles and other mouth-parts, which with the eyes are darker 

 than the other parts. The legs are rather long and stout and the anal 

 segment is obtusely and roundedly produced. The newly hatched 

 larva measures about one-sixteenth of an inch in length and the full- 

 grown larva about five-sixteenths of an inch. Descriptions of the 

 larval stages, as given by Merrill (21), follow: 



First Stage. When the yellowish larva first frees itself from the egg the 

 spines are closely appressecl. As the chitin dries, the spines become erect and 

 are seen to be branched at and near the tip. Later the tips of the branches be- 

 come dai'ker. The larva is about 1.3 mm. long by .6 mm. wide. The body 

 tapers sharply in the abdominal region and is recurved downward. There is a 

 row of four spines across the front of the rather pronounced pro-thorax. On 

 the rest of the body there are six longitudinal dorso-lateral rows, the spines of 

 the outside rows being very small and very few. * * * 



Second Stage. After the first moult the larva is 2 mm. long and the tip of 

 the abdomen is slightly more curved than in the first stage. The spines are 

 longer and more branched. The dark tips are not so pronounced. The rows 

 of spines are the same in number but more distinct. * * * 



Third Stage. After the second moult the larva is 4 mm. long. The spines 

 are longer, more branched from the sides, and dark tipped. The rows are now 

 easily seen. In this stage the larva seems to be rather humpbacked, the 

 highest and widest portion of the body being about the middle portion. The 

 abdomen tapers sharply, the anterior end slightly, only. * * * 



Fourth Stage. At the beginning of the fourth stage the larva is 5.4 mm. long 

 and it increases to nearly 1 cm. in length before the fourth moult. The chief 

 difference between the larva in this stage and in the last is in the size. 



THE PUPA. 



The pupa (fig. 1, c; PL V) is ovate in outline, and approximately 

 the size of the adult. It is 3'ellow T with brown markings. Anteriorly 

 it is roundedly subtruncate and posteriorly tapers strongly toward 

 the apex. The surface is sparsely beset with bristle-like setse and 

 long hairs. The head is folded down in front over the thorax and the 

 posterior legs reach below the wing-sheaths. The apex terminates in 

 two elongated processes, conical at the base and black at the ex- 

 treme tips. The larval exuviae are pushed down and form a protec- 

 tion for the last abdominal third of the body. (PL VI.) Length 

 7-7.5 mm. ; width 4—4.5 mm. 



