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 \vc 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 lowest 

 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. Ilaliday. 

 This was published in the Entomological Magazine for 1836. It is 

 entitled An Epitome of the British Genera, in the Order Thysanop- 

 teret, with Indications of a few of the Species. Although this article 

 was 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 are two- 

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

 veins; the two pairs are of the same structure ; they are naked, ex- 

 cept the marginal fringe of hairs ; and when at rest, they arc crossed 

 so as to lie upon each other upon the abdomen. 



This sub-order includes a single family, the Tubuliferida. And 

 only a single genus, Phlaeothrips, representing this family, was de- 

 scribed by Haliday. 



Phlixothrips. — Here belong the more common of the black thrips 

 which abound in the flowers of clover and daisy; they are also 

 found, as their name indicates, under the bark of trees. 



* Tubulifera: tubulus, a small tube; fero, to bear. 



