PHYSOPODA. 125 



misapplication of the name Thrips to this insect is often the cause 

 of confusion. 



In taking up the Physopoda, it seems very probable that we re- 

 turn again to near the foot of the insect series as represented by 

 living forms. This is indicated by the Campodea-like form of the 

 body, the presence of rudimentary abdominal legs in a European 

 species, and the Podura-like habit of jumping of many forms. * 



These insects have been placed in various positions. But the 

 structure of the mouth, and the character of the wings, throw them 

 out of any of the accepted orders. And now the majority of ento- 

 mologists agree in assigning them the rank of a distinct order. As 

 to the position of this order, it seems to me that it is the lowot 

 living representative of one of the lines of development of winged 

 insects, of which line the Hemiptera is the culmination. 



The Physopoda has not been thoroughly studied. The most 

 important paper on the insects of this order is by A. H. Haliday. 

 This was published in the Entomological Magazine for 1836. hi- 

 entitled An Epitome of tJie HritisJi Genera, in tJic Order Thysanop- 

 tera. with Indications of a few of the Species. Although this article 

 published more than a half century ago, and was intended only 

 to include the British genera, it is the most complete account we 

 have of the order. The following classification is compiled from it : 



Sub-Order I. TUBULIFERA.* 



This sub-order is characterized by the absence of a borer in 

 the females, and by having the last abdominal segment in both 

 sexes elongated, narrow, and tubular. The maxillary palpi arc 

 jointed, with the first segment very short ; the wings ,uv without 

 veins; the two pairs are of the same structure ; they .ire naked. 

 cept the marginal fringe of hairs; and when at re-t. they are CTO 

 so as to lie upon each other upon the abdomen. 



This sub-order includes a xjnglc family, the Tubulij \ml 



only a single genus, Pkluothfip^ re] .ng thi> family, \\.i- 



scribed by Haliday. 



* Phla-othrips. -Here belong the more common ^( the black tlnips 

 which abound in the flowtrs of clover and daisy ; th 

 found, as their name in-i .uder the lurk of trees. 



Tubullfcra: tut>ulut. a small tube; fcro, to bear. 



