MILLEPEDES AND INSECTS. 



551 



found in South Africa, and in various parts of the West Indies and South 

 America, as well as in Australia and New Zealand. Peripatus iuliformis 

 (Guilding), from the Island of St. Vincent, is about two inches long. (See 

 Fig. 24). 



Fig. 24. Peripatus iuliformis (Guild.). 



CLASS V.INSEGTA. 



INSECTS are by far the most numerous class of animals which inhabit the 

 globe at the present time. The actual number of species on our lists cannot 

 be much less than 300,000 ; and many thousands of new species are described 

 every year. In this country alone we have between 12,000 and 13,000 

 species, although our fauna is exceedingly poor, not only as compared with that 

 of tropical countries, but even in comparison to that of Con- 

 tinental Europe. Only a few families and orders of insects Number of 

 are at all adequately known at present, and those only as Species 

 existing in the best -explored countries. The late Professor of Insects. 

 Riley estimated the probable number of existing species of 

 insects at possibly ten millions ; and such estimates are generally far below 

 the mark. The alternative estimate of two millions, which is put forward 

 by some entomologists, seems to me to be ridiculously low, when we consider 

 that the world has been so 'badly explored that we are not yet acquainted 

 with a dozen species of Phasmidce, or stick-insects, from Madagascar, an 

 island which has been visited by many collectors, while the Phasmidce are 

 not a group of small and obscure insects, but one which includes many 

 very handsome and conspicuous species, and to which belong the largest 

 of all known insects. 



To take another illustration, Mr. E. Ernest Green is now working at a 

 monograph of the Coccidce, or scale-insects, of Ceylon. Very few species 

 were previously known from that island, and he will probably be easily able 

 to multiply them at least by ten. 



Nevertheless, insects, like the plants on which they feed, are becoming 



