84 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxvi. 



occurrence of apterous species without rudiments of wings, the condition that one 

 sex is so frequently winged while the other is wingless, that among the normally 

 winged species there appear individuals with reduced wings, that the latter phenom- 

 enon occurs especially toward autunm; all these are occurrences which take place to 

 a considerable degree in the Phytophthira. 



The manner of nourishment of Thrips, their life in larval colonies, the rapid and 

 successive development of each generation, the sucking of plant roots by the larviv, 

 the periodical swarming of nmltitudes of the winged species give to Thrips through- 

 out an Aphid-like character. 



Therefore we can not doubt that we must separate the Physapoda from the 

 Orthojitera s. 1., but we must still determine whether we may inc(jrporate them into 

 the Rhynchota. If we maintain the division of the insects into eight orders ( Thysa- 

 nura, Orthoptera s. 1., Rhynchota, Neuroptera, Lepidoptera, Diptera, Hymenoptera, 

 and Coleoptera) and include in these orders the aberrant Siphonaptera, INIallophaga, 

 Strepsiptera, the first in the Diptera, the others in the Orthoptera and Coleoptera, 

 then we must also consider the Physapoda as Rhynchota and divide the Rhynchota 

 into Heteroptera, Homoptera, and Physapoda. 



But if, according to Brauer's classification, we break up the conglomeration of the 

 Orthoptera s. 1. into several orders of insects equivalent to the well-defined Coleop- 

 tera, Hymenoptera, Lepidoptera, Diptera, and Neuroptera, and also consider the 

 aberrant Siphonaptera as a single order, just as the Bryozoa, Echinorhyncha, etc., 

 represent aberrant types of worms, then there is no necessity for destroying the unity 

 of the type of the Rhynchota by the incorporation of the Physapoda, but we can 

 erect for Thrips a new order, the phyllogenetic value of which we find in that they 

 have branched off from the line of the Orthoptera-Homoptera-Heteroptera where the 

 Orthoi)teroid characters of the Homoptera are not entirely suppressed, and that they 

 exhibit special mouth parts which morphologically still remain somewhat Orthop- 

 teroid, but functionally are quite Rhynchotoid. The Mallophaga with their Rhyn- 

 chota-like nervous system and their four malpighian vessels must have branched off 

 before the Physapoda. Their special connection with the Physapoda arises from 

 the fonn of the tracheal stigmata in the development of the thorax in which the 

 metanotum, as in the Physapoda, is larger than the mesonotum in contrast with all 

 Rhynchota and Orthoptera. If we collect the Mallophaga, Psocida?, and Termitid;e 

 as Corrodentia with Brauer, then we must place Physapoda in the system between 

 Corrodentia and Rhynchota. 



COLLECTION OF THYSANOPTERA. 



A.s the life habits of species of this order differ very greatly, the 

 methods of collection must })e varied according to the species. The 

 majority of these insects are to be found in flowers, grass, etc. ; many 

 are found exclusively in turf or near the surface of the ground; others- 

 are taken most commonlv under the bark of trees, on foliage, etc. 



For the grass-inhabiting species, I have found a short-handled sweep- 

 ing net, made of tine muslin, most serviceable. Other cloths may be 

 used, but the texture must be considerably tiner than that of cheese 

 cloth or many of the smaller species can easily pass through it and 

 escape. As a white background greatly facilitates the observation of 

 these small creatures, the contents of the net may be carefully exam- 

 ined by slowly turning it inside out without emptying it or the net 

 may be emptied and the contents be examined upon a sheet of white 

 paper carried for the purpose. Small phials serve as convenient reeep- 



