294 BULLETIN 45, UNITED STATES NATIONAL MUSEUM. 



Museum coutaius n fresh specimen, leiiicd ]\Iarch 20, 1SS2, by Dr. Riley 

 from Aleurodes sp. occurring on Acer dasycarpum at Arlington, Va., 

 while my collection contains a single specimen captured with the 

 sweeping net. 



Prof. Haldeman gives the following interesting facts respecting it: 

 "Parasitic on the larva oi AJcHrodcs corni ITald., of which it destroys a 

 great many. 1 found it with that insect beneath the leaves of Corniis 

 sericea on the margin of a water course. It leaps, walks, and flies with 

 facility, and when touched simulates deatli. The antennae are kept in 

 a constant state of vibration. I have kept them a week or more, liv 

 ing in confinement. The ova (crushed from the ovaries) are fusiform, 

 rounded at one extremity and produced at the other like the neck of a 

 flask." 



The insect described by Prof. Forbes as Elapius aleuyodis, reared 

 from Aleurodes aeeris Forbes, is evidently identical. 



Geoffroy has described an Aleurodes aeeris in Europe, and 1 would 

 here suggest the name .4. Forhcsii^ for l^of. Forbes's species. 



TRICHACIS Forster. 



Hym. Stud., Ii, p. 108 (1856). 



(Type, T. j;c.s/s Walk.) 



Head transverse ; the frons subcouvex, the occiput not or only deli- 

 cately margined ; ocelli 3, in a triangle, the lateral ocelli their width away 

 from the margin of the eye. 



Antenna? lO-Jointed in both sexes, in 9 ending in a 5-jointed club, 

 the first and third funiclar joints minute, the second lengthened, as long 

 as the pedicel and first funiclar joint tvigether ; first club joint the shortest, 

 the last the largest, ovate; in S with the club thinner, the joints more 

 elongate, cylindrical, the first and secondfuniclar joints h)ng, not small, 

 or the first very minute, the second swollen. 



Thorax ovate, the pronotum produced into a slight neck anteriorly; 

 mesonotum conv^ex, about twice as long as wide, with 2 deep furrows; 

 scutellum somewhat elevated, with a tuft of hair at tip, but without a 

 thorn or tubercle; metathorax very short, witli two me<lian k<'els, the 

 pleura x^ubescent. 



Wings ciliated, veiuless, the sul)niarginal vein traceable basally. 



Abdomen in 9 conic-ovate, -t-jointed, the first segmeutpetioliform, stri- 

 ated, the second as hmg as the two following together, with 2 foveohe at 

 base, the third less than one-third the length of the fourth, with trans 

 verse rows of small punctures, the fourth or last conical, compressed 

 from above and below, margined, the apical half very flat or subcon- 

 cave, with stria; at base followed by a slight smooth prominence; in S 

 oblong-oval, 8-jointed, the last two segments very miiuite, segments 3, 

 4, and 5 nearly equal, usually with transverse rows of punctures. 



Legs clavate, the basal joint of hind tarsi more than twice as long 

 as the second. 



