XXIV. DIODONTUS. 187 
and the succeeding ; in size it is intermediate between the 
two. It appears to have been hitherto overlooked or 
mixed with the following species, from which it differs 
in the sculpture of the incisure between the dorsolum and 
scutellum, and also in size ; it appears to be not uncommon. 
Spe. &. tristis. V. d. Lind. 
ater, incisurd inter dorsolum et scutellum consutd. 
length 21—3E lines. 
V.d. Lind. pt. 2. 76. 1. 
? Pemphredon minutus. & St. Farg. 10. 48. 2. 
Head black, shining, punctured, more thickly so on the face ; 
mandibles rufescent at their apex. 
Thorax black, shining, subpubescent; the dorsolum with a 
few scattered punctures, and having an impressed longitudinal 
line on each side forming a kind of epaulet to the tegule, and 
somewhat slightly longitudinally striated down its centre, occu- 
pying about the third of its superficies, in some the striz are 
seen only at the base and apex; the deep incisure that separates 
the dorsolum from the scutellum consute ; the pectus transversely 
wrinkled ; the scutellum very shining, with a very few scattered 
punctures, and sometimes having a longitudinal line in its centre ; 
the metathorax very rugose; the wings iridescent, with their 
nervures piceous, and a dark cloud about their middle ; the legs 
black, with the tarsi sometimes nigro-piceous, or a shade 
lighter, but generally black; the calcaria testaceous; the an- 
terior tarsi very slightly ciliated, and the intermediate and pos- 
terior tibize spinose. 
The abdomen black, ovato-conic, subpubescent, and very 
minutely punctured ¢. 
The ¢ differs in having the head and thorax more deeply 
punctured ; the striz of the dorsolum obsolete ; the legs, with 
the anterior tibiz in front, and their tarsi, entirely yellow; the 
intermediate and posterior tibize yellow-testaceous, with the ex- 
ception of an irregular spot in front, which sometimes encircles it 
