340 T. D. A. COCKKRELL. 



to Kansas and Texas; and there is another of the genus in Nevada. 

 Andrena, which is also European, has many North American species. 

 Thus, of the above four generic types, two, Megacilissa and Nomiasn^m 

 to belong to the Southern fauna ; and the other two, to the boreal. 



HALICTIN^. 



386. Prosopis varifrons Cr., Cusack Ranch, Aug. 3, and near West Cliif. 



387. " basalis Sm., Cusack Ranch (M. E. Cusack). Also high-alpine. 



388. Colletes sp. West Cliff, May 19. 



389. Agapostemon sp. West Cliff, May 23, at flowers of Eanunculus cymhalaria. 



and May 2.5, at Senecio flowers, abundant. A bright green species. 



390. A. melliventris Cr. ? In September, as I was driving past Dismore's 



Ranch, just within the Custer County boundary, I saw a bee which 

 seemed very like the figure of this species in the Rept. Wheeler Sur- 

 vey, which, as it happened, I had been looking at a few hours before. 

 Unfortunately, I could not catch it. 



391. Halictus sp. West Cliff, May 23, at Ranunculus cymhalaria. 



Prosopis varifrons seems confined to Colorado, but P. basalis ranges to 

 British America. Colletes is widely distributed from Canada to Florida, 

 etc., besides being European. Agapostemon and Halictus go south to 

 Florida, etc., but although there are many United States species of 

 Halictus, none, except trisonatus from Nevada, seem to have been 

 found on the Pacific slope. 



Sphecodes, a boreal genus, was not noticed in the mid-alpine; but in the 

 high-alpine region I met with S. dichroa Sm. In Europe this genus 

 shows a tendency to become split up into numerous closely allied but 

 distinct species, so that in the British Is. alone there are fifteen specific 

 forms; in North America this species-forming tendency has not shown 

 itself, so far as can be judged from published information, the whole 

 of North America having but five species. 



CRABRONID-^. 



392. Crabro packardii Cr., near Swift Creek. 

 .393. " vicinus Cr., near Swift Oeek. 



394. " bellus Cr., near Swift Creek. 



395. " gracilissimus Pack., near Swift Creek. 



.396. " sexmaculata Say, Willow Creek, Cusack Ranch, Aug. 22. 



397. Trypoxylon frig-idum Sm., Cusack Ranch. 



398. Oxybelus u. sp. Ashm., near Swift Creek. 



Crabro sexmaculata is boreal, but the others are only known from Colo- 

 rado. T. frigidum is also a boreal type. The genus Oxybelus is widely 

 distributed in America, and has five Colorado species. 



PEMPHREDONID^. 



399. PassalCBCUs mandibularis Cr., Cusack Ranch (M. J3. Cusack); and near 



West Cliff. Also high-alpine. 



400. Passaloecus cuspidatus Sm. West Cliff. 



401. Cemonus inornat^is Say, Cusack Ranch. 



402. Stigmus fraternus .Say. West Cliff, by sweeping, July 25. 



403. Pemphredon concolor Say. West Cliff. 



