48 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 68 



of the scale, then it infiltrates through the pores and forms a film 

 over the entire dorsal surface of the scale. The bases of some of 

 the scent scales are innervated. 



6. GLANDS AT FEMORA-TIBIAL ARTICULATIONS OF BEETLES AND ANTS 

 AS SCENT-PRODUCING ORGANS 



Lacordaire (1838) was one of the first investigators to describe 

 the phenomenon of ejecting liqviid from various parts of the body 

 of certain insects. He says that when Dytisciis and Gyrinus are 

 picked up, they emit through the articulations between the head, 

 thorax, and abdomen a milky and fetid fluid. Meloe emits from the 

 articulations of the legs a yellowish-orange liquid whose odor is 

 not disagreeable. Coccinellidse and Chrysomelidse emit an analogous 

 liquid at the same places, but it has a diflferent odor and is quite strong. 



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

 tibial articulations of Timarcha, Coccinclla, and Meloe. He thinks 

 that the discharged liquid is blood for the following seasons : ( i ) 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 presumably 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. 



Magretti (1881) imagines that the discharged liquid from Meloe 

 is secreted by gland cells in the legs. 



Beauregard (1885) saw a layer of large hypodermal cells beneath 

 the chitin in sections through the articulations of the legs of Meloe, 

 He imagines that these large cells are gland cells. 



De Bono (1889) believes that the discharged liquid from Timarcha 

 is a glandular secretion. 



Cuenot (1890) says that the discharged liquid from the legs of 

 the meloid beetles, Cantharis, Meloe, Mylabris, and Cerocoma, is com- 

 pletely 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 destined 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 



