THE ENTOMOLOGIST. 243 



All the parasites hitherto discovered, and believed to infest 

 the Halicti, no doubt attack the smaller species of the genus: 

 H. nilidiusculus, H. minutus, H. aeratns and H. qiiadrino- 

 tatus, have been captured by myself attacked by Stylopidae, 

 and these would no doubt prove to be parasites of a very 

 minute size ; but in the autumn of 1857 I took specimens of 

 Halictus cylindricus, and also of H. albipes, infested with 

 parasites twice, if not three times, the size of those found in 

 the bodies of the minute Halicti : there is therefore no doubt 

 a most important discovery yet to be made, doubtless of 

 some new genus of Stylopidae. The parasites that I observed 

 in the bodies of H. cylindricus and H. albipes were females, 

 and these offered no distinctive characters from the other 

 female parasites in the bodies of the minute bees. 



It has been stated as a peculiar characteristic of these 

 bees that they burrow by night, " especially by moonlight, 

 when it is difficult to walk without treading upon them ; so 

 numerous are they, indeed, that they look like a cloud floating 

 close to the surface of the ground." I have had two or three 

 excellent opportunities of witnessing such a phenomenon 

 when on entomological excursions into Hampshire, and I 

 have repeatedly visited large colonies, at appropriate times 

 and seasons, but I never saw any bees on the wing after sun- 

 set : I have found the females turning up their little hillocks 

 of earth, ready to issue forth very early, on fine autumnal 

 mornings, certainly as early as six o'clock ; but they rarely 

 take wing, according to my observation, before nine o'clock. 

 The closest allies of these bees are undoubtedly those be- 

 longing to the genus Andrena; but their economy in one 

 respect differs not only from the genus Andrena, but from 

 that of all the other solitary species of ApidaB, excepting 

 only the genus Sphecodes. Early in spring some of the 

 larger species of Halictus make their appearance, but only 

 the females ; the other species appear in the same manner, 

 at intervals, all being abroad by the beginning of June : these 

 females, on appearing, immediately commence the formation 

 of their burrows, and proceed to deposit their eggs, but it is 

 not until the different broods are developed that males ap- 

 pear. The females, the produce of these broods, are fertilized 

 by the males, and these afterwards retire to some suitable 

 hybernaculum, and there remain throughout the winter 



