272 BRITISH BEES. 



3. argentata, Fabricius, <$ ? . 3-44 lines. (Plate 

 Leachella, Kirby. [XII. fig. 3 <J ? .) 

 Leachella, Curtis. 



4. odontura, Smith, <$ . 4^ lines. 



GENERAL OBSERVATIONS. 



Named from the great development of the labrum, 

 fjueya large, ^eiA.09 Up, which is characteristic of all the 

 Dasygasters, and also of some of the proximate Nudi- 

 pedes, those parasitical upon them, Stelis and Ccelioxys, 

 and which, too, resemble the sitos in the expansion and 

 dentated formation of their mandibles, although they do 

 not use them for the same purposes ; this again exhibits 

 an analogy of structure, that appears in the parasite to 

 be merely corroborative of identity of existence. 



These are more essentiallvsummer insects than the ma- 



m 



jority of the preceding genera, although some of them pre- 

 sent themselves with genial spring weather. The genus 

 may be separated into two distinct divisions by the pe- 

 culiar dilatation of the tarsi of the males of some of the 

 species, but such division is not indicative of a differ- 

 ence of habits, as is distinctly the case in the genus An- 

 thophora,su\d. in which these combined circumstances Mr. 

 Kirby suggested as acceptable for generic division, or, as 

 he called it, the institution of another family. But in 

 these we find in both divisions both wood-borers and 

 earth-tunnelers, and some species are indifferently either 

 as suits their accidental convenience. The general ap- 

 pearance of the insects is more that of ordinary bees, 

 and the sexes are more approximate in their habit than 

 is usually the case. 



With this genus commences essentially those desig- 

 nated as artisan bees, although Colktes might very 



