110 APID2E. 



still larvae ; on opening one cell it was found to contain two speci- 

 mens of Nomada sexfasciata. Since the former visit I have on 

 several occasions obtained the cells of Eucera, and have endeavoured 

 to find the larva of Nomada, but in vain. Perfect individuals of 

 N. sexfasciata have been found in the cells of Eucera on several oc- 

 casions, usually two in each cell, and once a pair of N. altemata. 



Although observation has proved that some species of JSfornadce 

 are constant in their parasitism on one particular species of bee, 

 others have been obtained from nests of as many as two or even 

 three distinct species of Andrenidse, also of Halicti. Nomada 

 sexfasciata is the parasite exclusively of Eucera longicornis, N. bo- 

 realis of Andrena clarJcella, N. fabriciana of Panurgus banksianus, 

 N. baccata of A. argentata, N. oclirostoma of A. labialis, N. late- 

 ralis of A. longipes, and N. germanica of A. fulvescens; whilst 

 N. varia is the parasite of Halictis cylindricus, N. solidaginis of 

 H. leucozonius ; all these are constant, as a rule, in their attacks ; 

 whilst N. ruficornis attacks various species, but has been found 

 usually most numerous where colonies of Andrena trimmer ana were 

 established. However, observation has shown that many species will 

 attach themselves to any species of bee which furnishes a suitable 

 provision for its larva. 



This genus of bees is of wide geographical distribution, although 

 it is almost exclusively confined to countries north of the Equator ; 

 only three exceptions to this are at present known, one being a 

 species from Brazil, and two from the Eastern Archipelago, one 

 from the Island of Timor, and the other from Ceram. The greatest 

 number of the species are of Europe and North America ; of the 

 former upwards of fifty are described, and about thirty from the 

 latter. The general catalogue issued by the British Museum in 1854 

 enumerates eighty-eight described species ; since that time the addi- 

 tions made from all countries will increase that number to about 

 one hundred. - The additions that may be expected from North 

 India, North China, and Japan will no doubt greatly increase the 

 species of the genus. All our British species emit, when taken, 

 most agreeable odours, in some species it being of a balmy sweet- 

 ness, whilst a few have a more pungent scent. This peculiarity is 

 observable in some of the genera of Andrenidse, Prosojois being a 

 genus the species of which are strongly aromatic. 



1. Nomada ruficornis. 



N. ferruginea, thorace lineis tribus longitudinalibus atris, abdo- 

 mine maculis fasciisque flavis. 



Nomada ruficornis, Fair. Ent. Syst. ii. 347 ; Syst. Piez. 390 $ . 

 Rossi, Faun. Etrus. ii. 112. 

 Panz. Faun. Germ. 55. 18. 

 Zatr. Hist. Nat. xiv. 50. 

 Schaf. Germ. Zeits. i. 279. 

 St.-Farg. Hym. ii. 498. 

 Smith, Zool. ii. 596 <$ $ j Bees Great Brit. 118. 



