ORDER THYSANOPTERA 87 



suctorial lice, or the sucking ticks or mites; but judging 

 from the serious results following the efforts of the animals 

 to rid themselves, and from the known irritation due to 

 anything crawling among the hairs or feathers, it cannot be 

 (K)ubted that they cause much annoyance and inconvenience 

 to the creatures that become their involuntary supporters. 

 The biting lice of cattle and horses are annoying pests 

 and demand the attention of the stockman. 



Order THYSANOPTERA. 



The species of this order are all very small and have 

 mouth parts intermediate between the biting mouth parts 

 of the Orthoptera and the suctorial mouth parts of the 

 Hemiptera. In some respects they may be considered as an 

 intermediate group between the Orthoptera and the Hemip- 

 tera, but not as a distinct connecting link between the two, 

 because in the matter of wings they have a specialization 

 of their own. They are minute, all very small, the largest 

 not over one-eighth to one-fourth of an inch in length. 

 Many are not over one-sixteenth of an inch long. They 

 have very slender bodies and slip around readily between 

 the parts of the blossoms of many different kinds of plants. 

 The different stages may occur in the bloom, and they feed, 

 at least in large part, upon the soft tissues of the parts of 

 the blossoms, puncturing and corroding them so as to secure 

 the juicy contents. 



The mouth parts are drawn out in style-like form. Their 

 structure is partially like that of Hemiptera, but the styles 

 are not produced beyond the length of the head. They are 

 not capable of cutting and biting as the mouth parts of the 

 grasshoppers, nor are they strictly suctorial organs. The 

 wings are characteristic. In one division the wings are 

 narrow, with few veins and provided wath quite long marginal 

 setse which furnish a large part of the area of the wings. 

 The hind wings of this form also have setse but no veins. 

 Another division has wings very simple, without any vena- 

 tion, and provided with enormously long sette. They are 



