6 U.S. NATIONAL MUSEUM BULLETIN 243 



and other color markings often vary in translucence, whereas those in the 

 clear areas are quite hyaline. The thin film of the areolae is usually irides- 

 cent. Thus the color of the foliage on which the tingid feeds and rests can 

 always be seen through those windowlike areolae of the topcloak that 

 possess the property of transmitting rays of light. 



As the feeding injury develops, the various color changes effected on the 

 leaf — from green through brownish to yellowish white — are likewise 

 reflected through the panelike areolae to the degree that the cells are 

 pervious to light. Lacebugs themselves do not possess any ability to 

 undergo chameleonic changes in color. 



The immature stages present an altogether different external appearance 

 in yet other ways than those of the lacy topcoats of their parents. Instead 

 of the network, the dorsal surface of the nymph is smooth and plain (pi. 8) 

 or armed with simple or modified spines of various kinds and sizes (pis. 31, 

 33, 37). The dissimilarities between the imaginal and nymphal stages are 

 depicted in the illustrations of such forms as Litadea delicatula (pis. 7, 8) 

 from Reunion, Diconocoris capusi (pis. 30, 31) from Viet-Nam, and Ammianus 

 alberti (pis. 36, 37) from Africa, and Australotingis jranzeni (pis. 32, 33) 

 from Australia. 



The ability of the nymphs to crouch low and remain stock-still with 

 their bodies pressed close to the surface of the leaves are characteristics 

 inherited from their parents. Besides these behavioral traits, the castoff 

 skins, eggshells, scattered dots of brownish-black excrement, and the somber 

 color of the body also tend to make them less noticeable. The spines 

 (pis. 33, 37), tubercles, and hairs on the dorsal surface are likewise factors in 

 concealment. The nymphal stages of some species also possess glandular 

 spines. 



Neither adults nor nymphs imitate or simulate in color, form, or behavior 

 any animate or inanimate object in their habits. The species, in all life 

 stages, are relatively sluggish, completely defenseless, and without any 

 means or ways to fight back or even the speed needed to evade hungry 

 marauders. To escape enemies, they rely entirely on behavioral features 

 and camouflage. 



The feeding activities of some species of lacebugs cause the young foliar 

 leaves of their host plants to curl downwards. According to Horvath 

 (1929), the African tingid Onymochila dichapetali (pi. 17) causes extensive 

 leaf-curl on the foliage of its host, Dichapetalum cymosum (pi. 17), in the 

 Transvaal. The attack of the Japanese tingid Tingis comosa on the foliage 

 of its host plant, Artemesia sp., produces a similar type of down-curl (fide 

 Takeya); and, in India, the feeding of adults and nymphs of Corythauma 

 ayyari (Drake) produces a leaf-curl on Jasminum spp. (fide Livingston). 

 These are the only lacebugs so far known to effect this type of leaf damage 

 and thus may indicate their roles as vectors. 



The members of two genera of lacebugs are true gall-producing insects. 



