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



New Haven, 26 June, 1905, on pear tree (H. L. V.). Has 

 been recorded as nesting in the bark of pine trees, lining its nest 

 with clay. 



Pemphredon Latreille. 



As far as known the habits of the species of the genus Pem- 

 phredon conform in the main with those of the genus Passalce- 

 cus, but according to the records known at present the members 

 of the former genus prefer decaying wood for places to make 

 their nests. They also use aphids as the food for their larvae. 



The species falling in this genus may be divided into sub- 

 genera, but for the purpose of this paper the division is unneces- 

 sary for the small number of species known to occur in Con- 

 necticut. 



Key to Species. 



1. First cubital cell receiving only one recurrent vein; meso- 



scutum with strong transverse wrinkles 2 



First cubital cell receiving both recurrent veins 3 



2. Petiole nearly as long as first two joints of hind tarsi; 



anterior margin of clypeus, in female, subtruncate in mid- 

 dle; head of male much narrowed behind, not twice as 



broad as median length concolor 



Petiole subequal in length with first joint of hind tarsi; 

 anterior margin of clypeus, in female, angulate in middle; 

 head of male not much narrowed behind, fully twice as 

 long as median length ang^Iaris 



3. Mesoscutum of female with large, very close punctures; head 



of male very transverse, twice as broad as median length 



inomatus 

 Mesoscutum of female with large, widely separated punc- 

 tures; head of male nearly quadrate, not nearly twice as 

 broad as median length tenax 



P. inornatus Say. 



North Haven, 3 August, 1905 (H. L. V.). 



P. tenax Fox. 



North Haven, 3 August, 1905 (H. L. V.). 



°P. concolor Say. 



The male of this and the following species havj the flagellum 

 simple, the propodeal enclosure rugose, and the clypeus with a 

 wide emargination. 



°P. angularis Fox. 



