THiS ENTOMOLOGIST. 1^5 



tlay of spring and continuing to the end of August. The 

 black-faced male appears with Paivula at the end of March 

 or beginning of April, and lasts till about the end of May. 

 In the middle of May are to be found white-faced males, and 

 the female Nana; and, at the end of June or beginning of 

 July, there is another white-faced male, which differs from 

 the previous one, and with this male appears a female, which 

 at first sight might be mistaken forParvula; but, as Kirby 

 says in a footnote, the abdomen is of a different shape, and 

 it is less hairy. These three species, being found in 

 abundance close to the city, have enabled me to gel a good 

 series, with the dates of capture; and a close examination of 

 these has led me lo believe that Kirby was right in his belief 

 of the three species. 



Amongst tlie early bees is found one whose habits are 

 veiled in mystery; it is a bee without the necessary hirsuties 

 for conveying pollen. These are invariably absent in the 

 parasitic bees, but it does not necessarily follow that all bees 

 without these appendages are parasitic; for example, — the 

 genus Prosopis, or Hylseus, is entirely without them, but are, 

 nevertheless, constructive bees; the parasitic bee lays its 

 eggs on the honey and pollen collected by another bee, when 

 it finds one suited for its purpose. Many of these parasites 

 are constant in their attacks on certain species of constructive 

 bees; others (of which perhaps the best example is Nomada 

 ruficornis) attack several species varying greatly in size, and 

 consequently in the quantity of honey and pollen they collect 

 for the future young. The Nomada vary in size according 

 to the species they attack, the size being influenced by the 

 quantity of food. The above-mentioned insect varies from 

 three to six lines. As a rule there is not a great variation in 

 the size of the constructive bees, but amongst the Sphecodes 

 there is just the same variation in size as there is in the 

 NomadtC ; these insects are generally found running or flying 

 about the dry banks infested by the Halicti, which, in the 

 different species, vary as much in size as the specimens do 

 ill the species of Sphecodes. 



And it is not Halictus only that Sphecodes attacks (that is 

 supposing it to be parasitic), for in May last 1 found a large 

 colony of Aiidrena albicrus, which had made their holes in 

 the hard ground by the si Ic of a road, and flying about the 



