226 BEUTENMULLER, MONOGRAPH OF THE SESIID^E. 



Hy. Edw., and placed Sciapteron admirandus in the genus Tirista Walker. 

 The preoccupied name Harmonia Hy. Edwards (1882) is changed to Parhar- 

 monia and (464) Tarsa is united with Sciapteron. In 1896 (494) he changed 

 the preoccupied term Larunda Hy. Edwards (1881) to Gaea, and united 

 Phemonoe (1882) with Sannina Walker (1856). The genus Palmia is proposed 

 for Sciapteron prcecedens Hy. Edw., and Sanninoidea for Algeria exitiosa Say. 



In 1899 Beutenmuller (517) erected the genus Calasesia with Pyrrhotcenia 

 coccinea as the type. 



Habits of Imago. 



The moths with few exceptions fly during the day and in the brightest sun- 

 shine. Bembecia hylcziformis of Europe is said to be nocturnal, and very likely 

 our common B. marginata, which is a closely allied species, has the same habits. 

 I have taken this species at rest on flowers during the day. Late in the after- 

 noon the moths become sluggish and may be readily picked off from flowers or 

 the plants upon which they have been feeding or ovipositing. 



They emerge from the pupae early in the morning and are usually on the 

 wing before 10 a. m. Sanninoidea exitiosa (PL xxx, Figs. 16 and 17) emerge 

 from about 8 a. m. to 3 p. m., but nearly all hatch between 8 A. m. and 12 M. 

 Sesza pictipes, S. albicornis, S. acemi, S. bolteri, S. scitula, S. pyri, Memythrus 

 tricinctus, and M. simitlans have been observed to hatch before 10 A. M. The 

 imagos copulate soon after the wings are dry and the insect is ready to fly. The 

 copulation may last for half an hour or more, as is the case with Sanninoidea exitiosa, 

 and the oviposition may begin in three or four hours after the females emerge. 



It has been recorded that if the eggs are not fertilized by the male within 

 twenty-four hours, the female lays them unfertilized to get rid of them. These 

 eggs do not hatch, however. The eggs are pale brown in color ; ovate, disc- 

 shaped, with flat bottom. Their surface is minutely shagreened with feebly 

 raised lines forming hexagonal figures. 



Mimicry of the Imago. 



In general appearance in the field the Sesiidae very much resemble certain 

 wasps, hornets, and flies ; so much do they mimic these kinds of insects that 

 they may be readily mistaken for one or the other by a casual observer. Nowhere 

 among insects may there be found better examples of mimicry than in this family ; 

 every species, in some way, recalls well-known wasps or flies. Their long, narrow, 

 transparent or opaque, iridescent wings, and bodies banded or ringed with orange, 

 yellow, or red, as well as their flight give them a most striking resemblance to 

 Diptera and Hymenoptera. 



Algeria apiformis, in color and markings, is a very close imitation of 

 the large yellow hornet (Vespa crabro) which is found both in this country and 

 Europe. Vespamima sequoia and Bembecia marginata resemble certain kinds of 

 hornets {Vespa), owing to the yellow bands on the abdomen. Memythrus 



