344 .\KNTJAL REPORT SMITHSONHAN INSTITUTION, 1950 



a strictly limited number of plants and animals the struggle to survive 

 is intensified and a premium is placed on actively aggressive habits. 



Although mantids are thought to detect their prey mainly by sight, 

 the Carolina mantis can capture insects in the dark, and most of the 

 eastern species often mate and lay eggs in the dark. Some insects 

 are thought to have periods of rest comparable to the sleep of higher 

 animals. For example, certain wasps go to sleep with their mandibles 

 tightly clasped on weed stems, the body being held out vertical to the 

 stem. Some butterflies sleep on flowers and are plainly drowsy when 

 picked up at night. I have kept numbers of Chinese and narrow- 

 winged mantids in cages and have made a point of quietly going to 

 their cages after they have been in the dark for several hours and 

 inspecting them with a weak flashlight. Always they have been alert, 

 with a look of searching interest and with occasionally moving an- 

 tennae. 



Except for a few desert species, which dwell mainly on the ground, 

 mantids spend the bulk of their time climbing over weeds, grass, and 

 shrubbery, or just waiting. The kinds of insects available as food 

 will thus vary under different conditions. Mantids occasionallj^ visit 

 lights at night or frequent sweet materials to which other insects have 

 been attracted, and there they find good hunting. 



My observations on the Chinese and narrow-winged mantids show 

 that the majority of insects captured are consumed first at tlie head 

 or near the head, though occasionally the abdomen is eaten first. 

 When another mantid is caught, the head is often eaten first, but I 

 have seen the thorax eaten through near the base of the wings, with 

 the head, prothorax, and front legs dropping unnoticed while the 

 successful aggressor continued feeding steadily on the remainder of 

 the thorax and the abdomen. 



Some tropical mantids are specialized so as to resemble flowers, 

 or so that their colors blend with those of plant foliage. This is 

 thought to aid them in capturing prey, the hapless victims not sensing 

 the danger until it is too late. In southeast Asia a species {Hymeno- 

 pus coronatus (Olivier) ) that varies in color from white to pale pink 

 in the late nymphal stages has the habit of crouching amid certain 

 blossoms, the petals of which its legs and other body parts closely 

 resemble. Two other species, Gongylus gongylodes (Linnaeus) of 

 southeastern Asia and Idolum diabolicum Saussure of east Africa, 

 have brilliant blue colors on certain expanded parts of the body. Tlie 

 mantids display themselves on plants so that these colors are exposed 

 to the sun, and the widely adopted belief is that bees, flies, and other 

 flower-loving insects are thus lured to their doom. 



Hardly less remarkable is the superficial resemblance of a few 

 tropical mantids to other insects of the same environment that evi- 

 dently are distasteful to birds, monkeys, and other predators. The 



