OF WASHINGTON, VOLUME XVII, 1915 67 



and dispersion was needed but was it available? No one is mak- 

 ing studies of the insect and one turned to the literature. Piaget 

 is very satisfactory from the purely taxonomic viewpoint but the 

 few remarks he makes on habits were evidently based largely 

 on supposition. In fact, most of the statements go back to Leuck- 

 art's work published in 1863. l We find in it a mass of state- 

 ments about epidemics of psoriasis in the middle ages, about 

 kings and princes and high church dignitaries who succumbed 

 to gross infestation by lice. This is all interesting enough and 

 calculated to reassure us of our advance above the dark ages 

 but it does not supply the information we desire. As a matter 

 of fact entomology failed in this instance to furnish information 

 demanded in the investigations of an important and mysterious 

 malady. There are numerous cases in which exact knowledge 

 of insects under suspicion of disease transmission is required. 

 Some of them, like Stomoxys, are receiving attention but many 

 others remain to be studied. Investigators in related fields, 

 like those of the organisms found in the alimentary tract of 

 insects and of the pathological phenomena connected with insect 

 bites are doing much work, and entomologists working on the 

 distribution, dispersal, habits and development of insects will 

 have to bestir themselves most actively to perform their proper 

 share in the great problems of human health. Consider the 

 potential importance of the biting flies of the family Psychodidse 

 as suggested by the transmission of pappataci fever and verruga 

 in other countries. Our knowledge of the North American forms 

 is not sufficient to answer any one of scores of questions which 

 may arise in relation to the carriage of disease. Other families 

 of blood sucking flies like the Chironomidse are in the same con- 

 dition, and what do we know about the possible vectors among 

 the American Hemiptera? The biological side is largely terra 

 incognita. We know possibly as much about it as was known 

 about geography when Columbus discovered America. The taxo- 

 nomic side, though in a vastly more satisfactory condition, is 

 far from thoroughly explored. 



We digress at this point to note the vital importance of ento- 

 mological knowledge in connection with the investigation of 

 diseases that may be transmitted by insects. This was never 

 more clearly shown than in the case of a recent investigation in 

 the Canal Zone. 2 An equine disease caused by Trypanosoma 

 hippicum was under investigation and a question was raised about 

 the possible carriage of the organism by ants. As the investi- 



1 Leuckart, K. G. F. R. Die Menschlichen Parasiten, 1863. 



2 Darling, S. T. Tr. 15th Int. Congress Hygiene and Demography, 

 Sec. V, 1913. 



