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



Key to Subfamilies. 



Labrum small, very much shorter than the dorso-ventral 

 length of clypeus; intermediate tibiae with two apical spurs 



Stizin^ p. 692 

 Labrum very large, often longer than the dorso-ventral 

 length of clypeus; intermediate tibiae with one apical spur 



Bembecin^ p. 692 

 Stizin^. 

 This subfamily is represented in the State by a single species. 



Sphecius Dahlbom. 



S. speciosus (Drury). Giant Sand Wasp. PI, viii, Fig. 15. 

 Howard, Insect Book, PI. v, Fig. 21 ; Figs. 7-12. 



This is the largest Sphecoid known from the eastern United 

 States. It is large, robust, often more than 30 mm. long. It may 

 be briefly described as follows : Eyes slightly converging toward 

 the clypeus ; facial quadrangle narrow, at the antennae the width 

 is not as great as the diameter of the eye at the same place; ocelli 

 in a low triangle, the anterior one the largest ; flagellum thickened 

 apically; posterior calcaria flat, the longer one strongly curved. 

 Black; clypeus, a spot above labrum, mandibles (except piceous 

 apices), scape, spot on inner orbits, line on pronotum, tubercules, 

 and spots on the first three abdominal segments, yellow ; scutellum, 

 and mesoscutum sometimes, rufous ; wings yellowish hyaline, ven- 

 ation ferruginous. 



This species has often been called " the Cicada-killer " be- 

 cause it preys on Cicadae. Ashmead records it as provisioning its 

 nest, which is in sand, with the following: Cicada dorsata, C. 

 tihicen and C marginata. The original account of the habits of 

 this interesting species was published by Riley in " Insect Life," 

 Vol. 4, p. 248,- Figs. 32-38. 



On record from New Haven, August, 1905, and has been 

 taken by F. Knab at Milford on 15 August, 1900. The species is 

 sometimes very common locally, and often plays an important 

 role in the reduction of Cicadae. Other species of this genus 

 occur in the Western States. 



Bembecin^. 



Key to Genera 



I. Mandibles simple; maxillary palpi 3-jointed, labial palpi l- 



jointed Microbembex p. 693 



Mandibles armed with a tooth within; palpi different 2 



