348 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I4I 



that the crustacean and the cockroach, living under similar conditions, 

 developed the same general body shape. Rolling up into a ball is 

 nothing more than an exaggeration of a reflex common to many young 

 cockroaches, that is, an arched position vi'hich these insects assume 

 when they immobilize themselves in response to certain stimuli 

 (Chopard, 1938). 



There are cockroaches that resemble various Coleoptera and Hemip- 

 tera (Belt, 1874; Shelford, 1912; Hanitsch, 1915). Some look like 

 cerambycids, lampyrids, coccinellids, pentatomids, etc. Perhaps the 

 most striking examples are the resemblances of cockroaches in the 

 genus Prosoplecta of the Epilamprinae to beetles of the family Coc- 

 cinellidae; Shelford (1912) has figured a number of species of Pro- 

 soplecta together with the species of beetles which they seem to have 

 taken for models. WiUiams (1928) mentioned diurnal cockroaches 

 which by a combination of markings, shape, posture, and active flight 

 about vegetation suggest certain wasps. 



Unfortunately, practically nothing is known about the behavior of 

 these so-called mimics and models or their relationships with predators 

 in the field. For the most part, the examples are based on a compari- 

 son of pinned insects from museum collections (Burr, 1899) ; for 

 this reason Chopard (1938) believed that not much value should be 

 placed on superficial resemblances of this kind. However, we believe 

 that a lack of knowledge of cockroach mimicry is not a valid reason 

 for rejecting the idea that mimicry, if it occurs, may be of some bene- 

 fit in the survival of mimetic species. Certainly Cott's (1940) volu- 

 minous compilation of the literature on adaptive coloration should 

 make the most skeptic hesitate to conclude dogmatically that these in- 

 stances of mimicry are merely accidental and meaningless. 



XIX. THE BIOLOGICAL CONTROL OF COCKROACHES 



In the Navy [Japanese] a seaman who has captured 300 

 cockroaches will be granted one day special shore leave. They call 

 it "shore leave for cockroaches." The purpose is to promote ex- 

 termination of cockroaches in a warship because, on the one hand, 

 any warship suffers from numerous cockroaches, and, on the other 

 hand, any seaman likes shore leave . . . The formalities for a 

 shore leave for cockroaches are as follows. A seaman keeps 

 cockroaches which he captured (mainly B. gcrmanica, because 

 p. americana and P. anstralasiae are seldom found in Japan) in 

 a bottle or in a bag until the number reaches 300. Then he brings 

 them to the deck officer to get the confirmation that he has actually 

 captured more than 300 cockroaches. If the deck officer confirms it, 

 the seaman goes to a cabin where a petty officer reports that the 



