88 TRAP-DOOR SPIDERS. 



outside. An interesting account of the habits of this species will 

 be found in the Scientific Enquirer for May, 1886. The tube of 

 its nest is far shorter than those of the European species, and it is 

 therefore well adapted for observation in captivity. 



The greatest enemies of trap-door spiders in Europe are 

 lizards and centipedes, and the spiders are always on tlie alert to 

 guard against their attacks, so that if the outer door of a double- 

 door nest be opened, the spider immediately slams the inner door 

 to, for fear of its pursuers. If the latter be forced open or 

 removed, the spider will generally liee to the very bottom of her 

 nest, where she will be found crouched up in terror. Owing to 

 the complete concealment which the doors of the riests effect, the 

 only way of detecting them in countries where trap-door spiders 

 abound is to turn up all the likely-looking bits of earth until one 

 of the nests is found. Specimens of the top part of the nest, 

 showing the outer door, may be placed, with the surrounding 

 earth, in cardboard boxes of the proper size, and, alter filling the 

 tube with cotton wool, the best plan is to pour in plaster of Paris 

 to a certain height, fixing the portion of the nest and preventing 

 the earth from crumbling. Since the extension of the Parcels 

 Post to most parts of the Continent, a few of these curiosities 

 may occasionally find their way over to England. 



The Hessian Fly and its Parasites. — Observations upon 

 the Hessian fly, Cccidomyia destructor, made in North Britain, 

 brought to light the fact that it has not reached our island without 

 bemg accompanied (or followed) by several of its minute parasitic 

 enemies. Probably, it is in some measure due to the i)roceedings 

 of these that it has not extended over a larger area in those dis- 

 tricts where it first appeared. One of the most curious facts is 

 that these parasites have been verified as occurring chiefly in 

 Russia — at least, four of the species ; the fifth has been recorded 

 in America and also in Ciermany. This rather supports the 

 theory that the recent visitation came to us through imports from 

 Km^idi.— Journal of Horticulture. 



