74 THE CANADIAN ENTOMOLOGIST 



But a century later we find Nicolet reproaching naturalists that they have 

 attached but little importance to the study of the order; and in 1872 Lubbock 

 in his elaborate Monograph repeats the same complaint. Even to-day the 

 sum of Collembola literature, ^ — for the most part scattered through reviews 

 and ''/proceedings" in half a dozen different languages — comprises only a few 

 score papers. Nicolet's Memoir of 1841 and Lubbock's Monograph of 1872, 

 although both beautifully illustrated with drawings and coloured pictures of 

 an excellence seldom seen in modern insect books, are not nowadays of much 

 use to the systematist. Linnaniemi's large Memoir (1907-1912) on the Aptery- 

 gotan fauna of Finand is very useful to the American student, as many European 

 species occur here. Guthrie's "Collembola of Minnesota" (1903) is the most 

 comprehensive American volume, but the collector in this part of the country'- 

 soon comes across numerous species not mentioned by Guthrie. However, Dr. 

 J. W. Folsom, of the University of Illinois, the well-known authority on the 

 Order, has lately published several exhaustive memoirs on certain of the North 

 American sub-families, and I understand has others in preparation, so we may 

 hope to have soon accurate and authoritative descriptions of all the known 

 species on this continent. And we should be glad of this, for the Collembola 

 are well worthy of study. The economic entomologist with his mercenary 

 instincts may elect to ignore them, but their exceedingly primitive development 

 makes them intensely interesting to the student of insect genealogy; while the 

 astonishingly wide dispersal of some of their species and genera over the globe 

 points to the immense antiquity of the Order, and sets some hard problems for 

 the geologist to account for the primordial distribution of land and water. 



If the bees and the ants be regarded as the aristocrats of the insect world, 

 we must look on the springtails as belonging to the submerged tenth. They 

 are among the most primitive of the "six-leggers." Some writers class the 

 Thysanura as the lowest of the true insects, while others confer that doubtful 

 honour on Berlese's Mirientomata; but all agree in placing the Collembola second 

 on the list, only one step above the simplest known hexapods. The Order is 

 divided into two suborders: the Arthropleona and the Symphypleona — which 

 may be translated as the "Jointed-abdomens" and the "iTogether-grown- 

 abdomens." The terms well express the difference in the appearance of the 

 two divisions. The Arthropleona, which are considered the more primitive, 

 have a well-marked head carried horizontally and bearing a pair of antenna^ 

 usually four jointed (but six jointed in one genus). The thorax consists of three 

 conspicuous segments each with its pair of rather short legs, and the elongated 

 abdomen is made up of six distinct divisions. In the Symphypleona the head is 

 vertical, the constricted prothorax simulates a neck, while the other thoracic 

 divisions arc fused with the abdomen into an unsegmented globose body, the 

 insect somewhat resembling a minute spider. (See plates III and IV.) 



All the Collembola are without wings, and as no trace of these appendages 

 can be found in the embryo at any stage of its growth, it is apparent that the 

 wingless condition is primitive, and not the result of degeneration, as in the 

 case of numerous other insects. Typically the mouth-parts of both sub-orders 

 are withdrawn within the head, and are adapted for chewing, but in a few 

 genera they project in a suctorial cone. 



