CIRROSPILUS ESURUS. 



195 



FIG. 40. Chalcis ovata. 



head, and, upon breaking them open, the abdomen is found to be filled 

 with excrement of the larva, and the cast-off skins of larva and pupa. 

 Fig. 40 shows the ovate chalcis enlarged, 

 and also a chrysalis of Aletia pierced by 

 the exit of the parasite. 



We can find no published record of the 

 fact of the parasitism of this insect upon 

 the cotton-worm, and are not aware that 

 it \vas bred prior to 1878. 



The following is Say's original descrip- 

 tion of the insect : 



C. OVATA. Robust, black ; feet yellow, tbighs black at base, bead with a golden re- 

 flection. 



Inhabits Obio and Pennsylvania. 



Head black, with golden sericeous hair, which is indistinct on the vertex ; antennae 

 testaceous beneath towards the tip ; stethidium with dilated, dense punctures, a little 

 sericeous with golden hair; scale covering the base of the wings, yellow; wings 

 hyaline ; nervures fuscous, at base pale yellowish ; feet bright yellow ; basal half of 

 the anterior pair of thighs black ; posterior thighs smaller than the abdomen, black, 

 with a yellow spot on the tip above, dentated on the posterior edge ; posterior tibiae 

 pisceous on its basal incisure ; terminal spine robust, shorter than the first tarsal 

 joint ; first joint of the posterior coxae with a robust tooth above near the tip ; abdo- 

 men subovato, polished ; first segment nearly glabrous, second segment hairy on each 

 side, remaining segments hairy near their tips. Length one-fifth of an inch. 



CIRROSPILUS ESURUS, Eiley. Another chalcid parasite, of much 

 smaller size than the last, was reared in con- 

 siderable numbers from the chrysalides of the 

 cotton- worm during the summer of 1878. It 

 proved to be a new species of the genus Cir- 

 rospilus, and has been described under the 

 specific name csurus by Professor Kiley, in 

 a recent number of the Canadian Entomol- 

 ogist. His description is as follows : 



2. CIRROSPILUS ESURUS, n. sp. Length 1.5 mm . 

 Dull black ; knees, tibiae and tarsi yellowish, the 

 posterior tibiae sometimes dusky. Eyes with scat- 

 tered, short bristles. Antenna, of the $ 9-jointed, FlG " 41.-Cirrospilus esurus. 

 with the joints of the flagellum subequal and beset with bristles, the ninth joint small. 

 Antennae of the $ 8-jointed, the fourth and fifth shorter than the second and third, 

 the three apical joints forming a club. Thorax above microscopically punctate ; parap- 

 sides distinct and elevated ; scutellum with a longitudinal, impressed line on each 

 side. Wings hyaline, pubescent, but the cilia short ; base of ulna uneven ; radius not 

 developed. Abdomen short and sessile, ovate. Described from numerous specimens 

 reared from the pupa of Aletia argillacea. 



This species shows relationship with the genus Tetrastichus, Halliday, and may ul- 

 timately be referred there. For the present I prefer to place it in the older genus. 



It is then a little black fly only about six-hundredths of au inch in 

 length, with yellow legs. From their small size, many of them can find 

 their sustenance in a single cotton- worm, and many of the adults were 

 bred from a single chrysalis. 



