BEES OF GREAT BRITAIN. 145 



^gate, the second rather longer than the first, the third and fourth 

 minute,, placed at the side and near the apex of the second joint. 

 The maxillary palpi three-jointed, the basal joint very short, 

 thick and subglobose ; the second joint not so thick, but of about 

 the same length ; the apical joint of equal length, but slender 

 and cylindric. The labrum elongate, transverse at the base and 

 produced at the lateral angles. Thorax globose, the scutellum 

 armed with a tooth on each side ; the superior wings with 

 one marginal and two submarginal cells ; the marginal cell nar- 

 row, elongate, and rounded at the apex ; the second submarginal 

 cell receiving the two recurrent nervures, the first near its base, 

 and the second near its apex. Abdomen conical, acute at the 

 apex in the females ; in the males the apex is dentate. The 

 claws simple in the females ; in the males bifid at their apex. 

 The males have their anterior coxae toothed. 



The bees belonging to the genus Coelioxys are parasitic upon 

 those of the genera Megachile and Saropoda ; from cocoons of 

 M . circumcincta Mr. Waterhouse obtained a species of Ccelioxys 

 in the year 1835. I have frequently bred C. simplex from the 

 cocoons of the same bee, and C. mfescens from those of M. 

 Willughbiella. Some years ago I found a species of C&lioxys in 

 the cells of Saropoda ; it was new to the British list, and de- 

 scribed under the name of C. umbrina ; the individuals found 

 in the cells were clothed with pale yellowish-brown pubescence ; 

 when once exposed to the sun this colour becomes cinereous. 

 The species occurs in profusion in Sandown Bay, Isle of Wight, 

 where Saropoda bimaculata also abounds. C&lioxys Vectis is 

 also very abundant in the same locality. 



The species of this genus are difficult to determine ; hitherto 

 three have been commonly associated as one. Dr. Nylander 

 has adopted an excellent distinctive specific character ; I 

 have availed myself of it in the discrimination of the British 

 species ; it must, however, be admitted, that excellent as the 

 character alluded to undoubtedly is, yet we must not forget, 

 that a species is not as it were cast in a mould, but admits of 

 a degree of variety, still however retaining intact the broad and 

 distinguishing characteristic. The distinctive specific character 

 employed, is the form of the plates of the apical segment of the 

 abdomen, the inferior plate being not only of a different form in 

 the species, but also of a different relative length as compared to 

 the superior plate ; in some species the two plates are of nearly 

 the same length, whilst in others the inferior plate is half as 



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