214 Annals E7ttoniological Society of America [Vol. IX, 



The ejection of a liquid from the articulations of the rudi- 

 mentary wings of certain Orthoptera has been studied by 

 Cuenot (1896a) and others. 



Izquierdo (1896) says that liquids discharged by insects as 

 a means of defense may be divided into three groups: (1) Those 

 from organs which are furnished with glands. Such organs are 

 found in all the families of insects and their exits may be found 

 in the thorax, abdomen, at the anus or in the last portion of the 

 intestine; (2) liquids which are discharged from the femoro- 

 tibial articulations; and (3) liquids that are discharged from 

 the mouth. 



From the preceding it is seen that liquids may be discharged 

 from various parts of the body of insects and that this phe- 

 nomenon is not restricted solely to beetles. 



Leydig (1859) was the first to make sections through the 

 femoro-tibial articulations of Timarcha, Coccinella and Meloe. 

 He thinks that the discharged liquid is blood for the following 

 reasons: (1) No gland cells nor glandular apparatus of any 

 kind were recognized; (2) the discharged liquid and blood have 

 the same color; and (.3) the discharged liquid contains pre- 

 sumably blood cells. He admits that this view is not well 

 founded because he could not find any openings in the articular 

 membrane through which the blood could pass. 



Cuenot (1890) says that the discharged Hquid from the legs 

 of the meloid beetles, Cantharis, Meloe, Mylabris and Cerocoma, 

 is completely odorless, but it is slightly poisonous. He thinks 

 that this liquid is blood, although he did not study sections 

 passing through the articulations. The same author (1894) 

 states that when one touches Timarcha, Adimonia, Coccinella 

 or Meloe, the beetles at once feign death. They fold the legs 

 and antennae under their bodies, fall to the ground and for a 

 longer or shorter time assume a perfectly inactive attitude des- 

 tined to deceive their enemies. At the moment when the insects 

 roll on the ground, drops of a slightly viscid liquid are ejected 

 from the mouths of Timarcha and Adimonia, but from the 

 femoro-tibial articulations of the coccinellids and meloids. 

 This liquid is yellowish or reddish in color. The discharged 

 liquid of Coccinella has a strong and very disagreeable odor, and 

 that of Timarcha is odorless, but has a persistent and astringent 

 taste. He proved by experiments that this liquid is for defense. 



