676 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull. 



as using aphids as food for their young. Ashmead also records 

 one species, T. collinum Smith, as nesting in hard sand. If all 

 these observations are proven to be correct, the genus will be one 

 of very diversified habits. For a very pleasing account of T. 

 albopilosum Fox and T. rubrocinctum Packard, see Peckham, 

 Bull. 2, Wisconsin Geological and Natural History Survey, 1898, 

 chapter viii, pp. 77-87. The species of this genus are parasi- 

 tized by various species of Chrysididae. 



Key to Species. 



1. Dorsal aspect of propocleum smooth or sparsely punctate.. 2 

 Dorsal aspect of propodeum striate, distinctly sculptured.. 3 



2. Postocellar line slightly shorter than ocellocular line; wings 



dark, subviolaceous politum 



Postocellar line very much longer than ocellocular line; 

 wings subhyaline excavatum 



3. Dorsal aspect of propodeum without a median sulcus 4 



Dorsal aspect of propodeum with a median sulcus; small, 



opaque, black species 5 



4. A strong projection between bases of antennae; abdomen in 



part red tridentatum 



No projection between bases of antennae; abdomen black 



clavatum 



5. Produced portion of clypeus truncate frigidum 



Produced portion of clypeus strongly bidentate bidentatum 



T. politum Say. Howard, Insect Book, PI. vi, Fig. 6. 



This species has usually gone under the name albitarse 

 Fabricius. The male was described by Kohl under the name 

 neglect um. It is the largest species in the State, being about 18 

 mm. long. The posterior trochanters of the male are unarmed, 

 but the first ventral abdominal segment has a hooked process. 

 The habits of the species have been described by various authors, 

 but under the name albitarse. The Raus have a good account of 

 the habits of this species in Jour. Animal Behavior, 1916, vol. 

 6, no. 1. 



Hartford, September and August. 



T. excavatum Smith. 



Length about 10 mm. Pubescence white, mesonotum smooth, 

 shining. This species is said to occur from Jamaica to the New 

 England States. It has been taken in the State, but no definite 

 localities are available. It is said to nest in stems of Syringa. 



