112 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. x.wi 



Perhaps it may not be too much out of place here to speak more par- 

 ticularly of other movements aside from flying. The Tubulifera are 

 very slow and deliberate in their movements, both in crawling- and 

 fl3dng, and the}^ never spring or run. Terebrantia vary in this 

 respect, though in general they are much more active, and many run i 

 quite rapidly and take flight quickly. Some possess a power of 

 springing which is well developed and often used in place of flight. . 

 The abdomen, head, and prothorax are raised and the little creature > 

 balances itself by its middle legs. Then suddenly the upraised parts- 

 arc })rought down together and the insect is thrown a considerable; 

 distance by the force of the contact. 



DEVELOPMENT. 



O'viposition. — As may be inferred from what has been said of the 

 sexual apparatus of the two suborders, each has its own method oft 

 oviposition. The Terebrantian female cuts a slit with her saw through i 

 the epidermis and deposits her eggs singly in the tissue of the plant. 

 The process of oviposition is as follows in AnaphothrijJS strlatus and! 

 will doubtless hold in most points for the group: 



The abdomen is raised somewhat and the ovipositor is let down 

 from the sheath till it is nearly ai right angles to the Ijody. The • 

 abdomen is arched to bring the weight of the body to l)ear upon the 

 slender saw, the valves of which are then moved back and forth upon 

 each other by j)owerf ul muscles in the ninth segment. The toothed I 

 blades are gradualh^ worked down somewhat oliliquely into the tissue, 

 and when the slit is sufficiently large there may be seen successive con- 

 tractions of the abdomen as the Qgg is pushed out between the valves- 

 of the ovipositor and under the epidermis till it is nearly concealed. 

 The entire operation requires about one and a half minutes, and upom 

 its completion the female moves off a short distance to rest or feed. 

 Occasionally the ovipositor becomes so firmly wedged in the plant as 

 to hold its possessor prisoner for some time, frequently until death i 

 results (469). 



I feel sure that Thr'ips 'perpleoc/iis and Chirothrips obesus will be found 

 to deposit their eggs externally. 



The number of eggs laid by a single female has been observed only > 

 in the case of Anaphothrlps driatns, from a numl>er of which an 

 average of from 50 to 60 was obtained, the maximum average from 

 a lot of 5 females being 72. These observations were made in the 

 laboratory upon females confined in bottles. The percentage of eggs 

 which hatched was also observed in this species and was found to 

 vary in the laboratorj^ from 35 to 40 per cent. It seems very probable 

 that the artificial conditions under which these experiments were 

 made must have in this case greatly reduced the percentage that 

 hatched below the normal. 



