BEHAVIOR OF SPIDERS AND OTHER INSECTS 435 



spreads to others on the advent of pellagrins; (5) in families 

 moving into non-pellagrous districts, children born in the former 

 district are pellagrous, while others are not; (6) the disease 

 is not hereditary; (7) it is not contagious. The advent of 

 pellagra in Kansas gave Hunter (42) an opportunity to conduct 

 a series of experiments which yielded the following results: — "(1) 

 the number of sand-flies is directly proportional to the number 

 of cases of pellagra; (2) the appearance of the cases of pellagra 

 is coincident with the principal broods; (3) just succeeding the 

 time of the principal broods the flies seem to bite more vigor- 

 ously; (4) sand-flies which have fed on human blood live several 

 days longer than those which have not been so nourished, thus 

 favoring an incubation theory for a parasite, if such there be; 

 (5) pellagra, thus far in Kansas, has appeared almost entirely 

 in one restricted locality; of nine cases recorded last year five 

 were traced back to one town; in this region flies are widely 

 distributed; (6) no direct evidence has yet been found which 

 would in any way warrant any conclusion with reference to an 

 association of the sand-fly in the determination of the etiology 

 of pellagra." Hunter hopes to continue his researches until 

 the problem is solved. 



PARASITISM 



Cummins (18) describes a sarcoptid mite of the cat; Howard 

 (37) several mites of the gypsy moth; and Bloeser (8) a hymen- 

 opterous hyper-parasite of Siphona plusiae Coq. 



Triggerson (85) gives a list of the numerous parasites of 

 Dryophanta erinacei. 



Isely (43) tells us that the Eumenidae of Kansas are parasi- 

 tized by the Bombilidae, the Tachinidae, the Ichneumonidae, 

 the Braconidae, the Mutilidae, the Myrmicidae and the Asilidae; 

 but that the most persistent parasites belong to the Chrysididae. 

 He believes that the turrets constructed about the entrances 

 of so many burrows of this group of insects are to prevent the 

 entrance of parasites. 



Muir (61) discusses the effect of parasites on the struggle 

 for existence. 



Fabre (23) describes the parasites of the mason-bees of his 

 part of France and states that he does not believe that parasitic 

 habits result from a love of inactivity ; for he finds that parasites 



