ROSS: EMBIOPTERA 515 



EMBIOPTERA 



Edward S. Ross 

 California Academy of Sciences 



Until very recently the Embioptera have never received serious specialized 

 study. Most of the past literature concerning this small order of secretive insects 

 has been but an incidental by-product of larger systematic projects of the au- 

 thors concerned. There are several reasons for this. First, the order barely 

 ranges into Europe or the United States, the regions from which most syste- 

 matic studies have emanated. Second, no limited area possesses sufficient species 

 to warrant a regional study, and no species are known to be of economic im- 

 portance. Finally, the accumulation of specimens in museums is scanty and 

 scattered. Few entomologists ever see Embioptera on their field trips, let alone 

 collect them. When they do, they tend to secure only juvenile specimens, which 

 are of no value in the present period of systematic studies. 



Latreille in 1825 was the first to mention an embiid in the literature. Not 

 until 1832, however, was a species actually named. This was Olyntha Brazilien- 

 sis Gray. In 1837 Westwood named two more species, one of which was based 

 on a figure published by Latreille in 1829. Burmeister (1839), Rambur (1842), 

 Hagen (1842), Blanchard (1845), Lucas (1849) are the authors who wrote 

 about these insects before 1853. By then eight species names had been proposed, 

 of which two were very early and correctly suspected to be synonyms. 



In 1853 orders as we know them today had not yet been fully defined, but 

 it is evident that the distinctiveness of these insects was very early recognized 

 for Burmeister placed them at a group level comparable to the termites. Lucas 

 (1849) was the first to note that the embiids live in silk tunnels. The location of 

 the silk-spinning organs was an unsettled question; as recently as 1912, Ender- 

 lein stated that the glands involved were maxillary. Previously Grassi (1889) 

 and Melander (1902) had correctly located these organs in the fore tarsi. 



Hagen (1885), Krauss (1911), Enderlein (1912) each compiled the existing 

 knowledge of the order in monographs. Navas (1918) reviewed the South 

 American species in a single treatment. None of these workers had much, if 

 any, field knowledge of the Embioptera. It may be concluded that almost all 

 this work suffered from a failure to make good microscope preparations of the 

 male abdominal terminalia and to utilize i)roperly the complicated details of 

 these structures in classification. Too much emphasis was placed on easily ac- 

 cessible wing venational characters, particularly the branching of the radial 

 sector. It is now evident that one type of wing venation has independently 

 developed on at least three different evolutionary lines. Apterism in the male 

 also led to confusion in defining genera. Navas added to the burden of future 

 students by occasionally basing new species on females or juvenile forms. 



Consett Davis in 1936 commenced an intensive study of the Australian Em- 

 bioptera and described the genus 3Ietoligotoma comprising a surprisingly large 

 array of species and subspecies based on good characters in the male genitalia. 

 Earlier workers, however, would certainly have regarded these, on the basis of 

 superficial features, as only one species. Until his accidental death in 1944, Davis 



