HOW TO KNOW THE IMMATURE INSECTS 



15a. Mouth parts in form of a cone located between the ventro-caudal 

 margin of the head and the prothorax showing maxillary palpi 

 and inconspicuous labial palpi; mouth parts are asymmetrical in 

 that only one functional mandible exists which may project a 

 short distance from tip of mouth-cone; tarsi smalL apparently 

 1-segmented, clawless and possess- single, protrusible pads; body 

 cylindrical, usually less than V& inch long and pointed at caudal 

 end. Fig. 67 Order THYSANOPTERA 



Fig. 67. Green house 

 thrips, Heliothr i p s 

 haemorrhoidolis 



(Bouche). 



Approximately 3,100 species of thrips have been 

 described. They are found among all kinds of 

 growing vegetation, as well as in wood and fungi. 

 They have the habit of curving the apex of the 

 abdomen upwards. They are generally four in- 

 stars before the adult stage is reached. Partheno- 

 genesis is of frequent occurrence. 



A favorite feeding ground for thrips is within the 

 flowers of plants where they often do heavy dam- 

 age. Both adults and nymphs may be readily 

 shaken from flowers out upon a white cloth or paper 

 and picked up by a small brush moistened in the 

 preservative in which the specimens are being 

 placed. A separate vial should be kept for each 

 species of plant and the species of plant recorded 

 on a paper slip with lead pencil and put in the vial. 



15b. Mandibles and maxillae usually enclosed 

 within a trough-like tubular labium which 

 usually projectSL caudad between the thoracic 

 legs; labium may be absent, if labiiun is cone- 

 shaped, maxillary palpi and labial palpi are 

 absent. Fig. 68 16 



■--U.Aai'-'M 



Fig. 68. Piercing 

 and sucking mouth 

 parts. 



38 



