RILEY SARRACEXIA INSECTS. 237 



Xanthoptera semicrocea Guen. £'^^— Globular, slightly flattened 

 at top and bottom ; 0.02 inch in diameter. Color, when mature, grayish. 

 With about 35 vertical ribs of a paler color, some of them anastomosing 

 and all becoming fainter toward the crown, which is smooth. 



Larva — Average length 0.8 inch. Thickest in the middle of the body, 

 and having but three pairs of prolegs. Color deep crimson, or lake-red, 

 the joints being deeply separated, and their borders, especially posterior- 

 ly, being white and strongly contrasting with the red. On each of joints 

 4, 5, 6 and 7 is a pair of more or less confluent, velvety-black, dorsal 

 patches, and a subdorsal, fleshy tubercle, the foremost a little the longest, 

 the others gradually diminishing in length. The other joints are each 

 ornamented with about a dozen small, dark, conical tubercles, trans- 

 versely arranged on 2 and 3, from a trapezoid to a square on 8, 9, 10 and 

 II. and on 12 in an opposite position to those on 9 : on the cervical shield 

 there are two rows and on the anal plate they are all brought close to- 

 gether. The red parts are n^ore or less thickly beset with short, fuzzy, 

 dark hairs, which are especially dense on the velvety patches and large 

 tubercles mentioned. Venter from joint 8 to anus pale. Head yellowish- 

 white with a deep brown transverse band around the mouth and the fore- 

 head, and an irregular spot of the same color on the top and on the front 

 of each lobe. Thoracic legs dark brown ; prolegs dusky. 



The newly hatched larva is pale, with the dark bands noticeable prin- 

 cipally on joints 4-7, the head uniformly pale-brown, and the tubercles 

 scarcely noticeable and surmounted by one or more stiff hairs. In the 

 second stage the tubercles become more prominent, but those on joints 

 4-7 are not relatively so much larger than the others. In the third stage 

 the characters of the mature larva are assumed, except that the colors do 

 not contrast so greatly, the short hairs are not so dense, and the head is 

 often unicolored. 



Many specimens examined, taken on both 5. 7 ariolaris and S. Jlava. 



Chrysalis — Uncharacteristic; varying from yellowish-brown to maho- 

 gany-brown in color; the head produced into a slight cone in front be- 

 tween the eyes, and the tip of the abdomen armed, in perfect specimens, 

 with two straight converging thorns, and several smaller curled hooks. 



Imago — Average expanse 0.8 inch. Colors, glossy straw-yellow and 

 black. Primaries with the basal half straw-yellow, varying from pale 

 chrotne to ochre; the terminal half brown-black with a gray and violet 

 reflection; the two colors sharply separated across the wing dt about a 

 right angle from costa. Secondaries same as terminal half of primaries, 

 but usually somewhat paler, especially toward base. Under surfaces uni- 

 formly purplish-gray, inclining to yellow basally, and with a somewhat 

 darker median shade usually discernible on primaries. Head black, with 

 palpi beneath and antennae yellow. Thorax of the same two colors, sharp- 

 ly separated across the shoulders. Legs yellowish, the tarsi with minute 

 spines, the spurs often with a spinous tip. Abdomen yellowish at base, 

 otherwise concolorous with secondaries. 



