1918] Alydince of the United States 261 



Pronotiini with lateral angles rounded, unaniied. Posterior angles 

 of metapleura acutely produced. Posterior femora reaching only half 

 way to tip of abdomen, pale at base, rufescent at apex. 



Venter pale, immaculate, darker toward apex. Sixth ventral 

 segment of female entire, produced posteriorly into a large flat mesal 

 lobe. Male with the hypopygium truncate unarmed at tip, completely 

 covering the genitalia except above. 



This Central and South American species has been recorded 

 from Texas^ and Florida-"^ It is the only member of subgenus 

 Stenocoris Burmeister and may be distinguished from the other 

 species from neighboring territory by the rufescent tips of the 

 femora and the produced, entire, sixth ventral segment of the 

 female. The body and legs are more elongate than those of 

 any other Coreid. 



Tribe Alydini Stal (18(37). 

 With one exception all the common North American 

 members of the Alydinse belong to this tribe and nearly every 

 species is widely distributed in the northern states. Owing 

 to great uniformity in appearance among the fifteen nearctic 

 species of the group, more or less confusion has existed in their 

 determination in the past, and the distribution of some species 

 is therefore in doubt. 



KEY TO GENERA OF ALYDINI. 

 a. Posterior tibiae strongly cvirved and produced into a distinct tooth near the 

 apex; lateral angles of pronotum acute, armed with a spine; openings of 



ventral scent glands distinct, with long sulci Hyalymenus 



aa. Posterior tibiae straight, not produced into -a tooth at apex (except 

 obsoletely in Bnrtinus). 



b. Openings of scent glands distinct, continued laterad as a sulcus 

 with a callous margin; antennae with first segment surpassing 

 apex of head, fourth sul:)equal to second and third segments 

 together. 



c. Antenna; with first segment longer than second; sixth 



ventral segment of female split on the medioventral line. 



d. Posterior femora without tooth near base, tibiae. 



unarmed; posterior metatarsus twice as long 



as two apical segments together Megalotoimis 



dd. Posterior femora with an obtuse tooth near base; 

 apex of posterior tibiae armed with a small 

 acute tooth; posterior metatarsus about one 

 and one-half times as long as two apical 



segments together Bnrtinus 



cc. Antennse with first segment shorter than second; sixth 



ventral segment of female entire Alydus 



bb. Openings of scent glands obscure or obsolescent, without a 

 callous-margined sulcus; antennae with first segment short, not 

 surpassing apex of head, fourth segment much shorter than 

 second and third together. 



c. Posterior tibiae unarmed; posterior margin of pronotum 



armed with an obsolete tooth or none Tollius 



cc. Posterior tibije armed with two rows of strong spines; 

 posterior margin of pronotum with a mesal tooth. 



Slaiiivocnenius 



