128 Mr. T. D. A. Cockerell on some 



on the inner hind margin behind the long fringe, which is 

 as in the species with highly modified tarsi, and is wholly 

 white viewed from without, but within the hairs are black 

 for their whole length. The four hindmost legs are black ; 

 middle tibia with a rufous spine at apex ; middle femora 

 quite stout ; spurs pale ferruginous ; middle tarsi with a very 

 long fringe of white hair behind ; hind tarsi with orange- 

 fulvous hairs on inner side ; abdomen fairly broad, parallel- 

 sided, punctured, second and third segments more or less 

 depressed at base ; first segment broadly excavated, so that 

 the dorsal (as distinguished from the anterior) surface is very 

 small ; pubescence very thin, white ; the hind margins of the 

 segments with dense white hair-bands, that on the first thin 

 and weak ; apex not at all emarginate, irregularly notched on 

 each side of the middle ; the three subapical ventral teeth in 

 the same transverse plane, the middle one long and sharp, 

 the lateral ones short, broad, and blunt. 



Hab. Las Cruces, New Mexico. One in the collection of 

 the Kew Mexico Experiment Station, probably collected by 

 Prof. Townsend. It had been studied by Miss J. E. Casad, 

 who left some descriptive notes. 



The following table separates the males of Megacliih with 

 peculiar front tarsi which are found in New Mexico, including 

 also the species from Colorado described above. All have 

 spines on the anterior coxae. 



Abdomen without hair-bands 1. 



Abdomen with hair-hands 2. 



1. Last joint of antennae dilated and flat- 



tened ; subapical ventral teeth of abdo- 

 men very large ; abdomen with much 



black hair Wootoni, sp. n. 



Last joint of antennae not or hardly 

 dilated ; subapical ventral teeth of abdo- 

 men small; abdomen without black hair, perihirta, sp. n. (Colo.) 



2. First joint of anterior tarsi produced to a 



free apex 3. 



First joint of anterior tarsi not produced 

 to a free apex 4. 



3. The free apex like the end of a finger ; 



hair-bands of abdomen fulvous Jidelis, Cress. 



The free apex not like the end of a finger ; 

 hair-bands vrhite pugnata, Say. 



4. Thorax very pubescent, the pubescence 



more or less ochreous or fulvous 5. 



Thorax not very pubescent, the pubes- 

 cence pale greyish to white 7. 



6. Flagellum slender, uot crenulat«^d beneath, latimanus, Say. 



Flagellum stout, crenulated beneath .... 6. 

 6. Pubescence of thorax yellowish grey .... comata, Cress. 



