NO. 2 RECOGNITION AMONG INSECTS McINDOO 49 



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. 



The ejection of a liquid from the articulations of the rudimentary 

 wings of certain Orthoptera has been studied by Cuenot (1896a) 

 and others. Cuenot (1896b) summarizes his investigations by saying 

 that Timarcha, Galeruca, Megalopus, coccinellids, and meloids among 

 the Coleoptera, and Eugaster and Ephippiger among the Orthoptera 

 possess the phenomenon of reflex bleeding. When disturbed they 

 feign death and eject drops of blood from the mouth, femoro-tibial 

 articulations and from the articulations of the first pair of wings. 

 In all these species the blood comprises toxic, caustic, or repulsive 

 products. It is an important means of defense against lizards and 

 batrachians. 



Lutz (1895) asserts that in the Coccinellidse, blood coming from 

 the distal end of the femur issues through a slit on either side of 

 the articular membrane which surrounds the chitinous rods (Selane) 

 to which the extensors of the tibia are attached. The blood exudes 

 by a forced contraction of the abdomen and by the flexors of the tibia, 

 and it is a voluntary act. It is a means of defense because the blood 

 is actually quite repulsive to insectivorous animals. In Timarcha, 

 Meloe, etc., as in the coccinellids, the device of ejecting blood from 

 the femoro-tibial articulations is to permit the blood to escape from 

 the legs rather than through the mouth. 



Packard (1895) states that many beetles, such as the oil beetles 

 Meloe, Cantharis, and Lytta, emit drops of blood from the femoro- 

 tibial articulations as a means of defense. The cantharadine pro- 

 duced by these insects is formed in the blood and in the genital organs. 

 It is so extremely caustic that scavenger insects feeding upon the 

 dead bodies of these beetles leave untouched the parts containing 

 cantharadine. Coccinellids are also protected by a yellow muci- 

 laginous and disagreeable fluid which is emitted from the sides of 

 the thorax. 



Izquierdo (1896) says that liquids discharged by insects as a 

 means of defense may be divided into three groups : ( i ) Those from 

 organs which are furnished with glands. Such organs are found in 

 all 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. 



