No. 22.] HYMENOPTERA OF CONNECTICUT. 327 



Coleocentrus Gravenhorst. 

 C. rufus Provancher. 



Length 17 mm. ; mostly reddish ; exserted portion of ovipositor 

 about as long as the abdomen, its sheaths blackish ; wings trans- 

 parent, almost clear, faintly tinged with yellowish brown. 

 New Haven, 30 May, 191 1 (A. B. O). 



Gelis Thunberg. 



Pezomachus Gravenhorst. 



Key to Species. 



Females. 



1. Head black or fuscous i 2 



Head reddish or yellowish; first abdominal segment distinctly 



dilated at tip 6 



2. Thorax at least partly black or blackish 3 



Thorax uniformly pale brown ottawaensis 



3. Thorax uniformly piceous brown or black; abdominal petiole 



entirely black; legs, or at least coxae and femora, black.. 4 

 Thorax bicolored 5 



4. Antennaa^ less than 40-jointed 9 



Antennae 40-jointed thripites 



5. Thorax with its anterior node reddish, its posterior node 



more or less black; first abdominal segment with prom- 

 inent tubercles and scarcely dilated behind them; antennae 



23-jointed gentilis 



Thorax black; antennae 19-jointed, reddish maculicollis 



6. Abdomen partly black or piceous 7 



Abdomen wholly reddish, sometimes very slightly infuscated; 



exserted portion of ovipositor as long as or longer than 

 abdomen; antennae 24- or 25-jointed unicolor 



7. Length over 4 mm., or not colored as in minimus; exserted 



portion of ovipositor at least about as long as first 



abdominal segment 8 



Length 2.5 mm. or shorter; first and second abdominal seg- 

 ments reddish; antennae 25-jointed minimus 



8. Anterior lobe of thorax with a median longitudinal groove; 



antennae 24-jointed dimidiatus 



Anterior lobe of thorax not as in dimidiatus; tip of abdomen 

 pale, petiole hardly dilated, third and fourth segments 



more or less blackish; antennae i8-jointed gracillimus 



g. Antennae i8-jointed nigrellus 



Antennae 24-jointed lymensis 



Males. 

 I. Without wings; first abdominal segment not considerably 



longer than propodeum 2 



With wings; head black; prothorax, legs, and abdomen, ex- 

 cept apex, yellowish or reddish gentilis 



