No. 22.] HYMENOPTERA OF CONNECTICUT. 689 



Stigmus Panzer. 

 The species of this genus are small, active, black wasps which 

 provision their nests, which are made in stems, or stumps, with 

 aphids. The only species found within the limits of the State 

 may be characterized as follows : 



S. americanus Packard. 



Head seen from above nearly quadrate; ocelloccipital line 

 three or more times as long as the postocellar line ; upper lateral 

 margin of the pronotum not dentate; sides of the pronotum 

 dentate ; pygidium subequal in length with the basal width. 



New Haven, 3 July, 1904; Momaguin, 5 August, 1905 (W. 

 E. B.). Bred from Rhus sp., collected, New Haven, 24 January, 

 191 1 (A. B. C, B. H. W.). This species is preyed upon by 

 Omalus corriiscans. 



Spilomena Shuckard. 



The habits of the species of this genus are probably similar to 

 those of the genus Stigmus. Only one species is known to occur 

 in the eastern United States. 



S. pusilla Say. 



Black with testaceous legs. 



Waterbury; Branford, 11 August, 1904 (H. L. V.). 



Passalcecus Shuckard. 

 As far as known the species of this genus make their nests in 

 rotten wood, decaying bark, in the galleries of wood-boring 

 insects, or in hollow stems of plants, and provision the same with 

 aphids or other small insects. According to observations made by 

 Westwood, two of the European species carry the aphids used in 

 provisioning their nests, with their mandibles. Only one species 

 has as yet been found in the State. 



P. annulatus Say. 



Third antennal joint subequal with (female) or much shorter 

 than (male) the fourth; the impressed lines on the mesoscutum 

 strongly foveolate; antennae of the male rounded out beneath, 

 long, slender. Black; scape beneath, mandibles (except apices), 

 tubercules and male flagellum beneath, white or yellowish white; 

 part of femora, all the tibiae and tarsi testaceous. 



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