8 AN ACCOUNT OF BRITISH FLIES. 



little progress is discernible in this science, unless it be in Arabian. 

 As the old longing for art and science left Greece and Rome, it went 

 to some extent to Arabia, and here we find some considerable ad- 

 vance in the study of insects ; amongst those Arabian botanists 

 whose names are known for their valuable knowledge of plants, and 

 who likewise paid no little attention to insects, must be mentioned 

 Rhazes and Avenzoa. 



The " dark ages " pass on, and what advance the study made 

 then we are unable to say. Not until about 1520 do we find the 

 subject renewed. In 1549 Agricola published his "De Aninialibus 

 Subterraneis," and in this we find the earliest systematic arrangement 

 of insects. Agricola in this work divided them into walking, flying, 

 and swimming groups, and he described a good many species. 

 Again, in 1557, another important work was brought out, namely, 

 " De Differentiis Animalium," in which an account of the insects 

 appeared. About fifty years later the Professor of Medicine at 

 Bologna, Aldrovandus, wrote a large folio volume on insects, " De 

 Animalibus Insectis," and his work was notable for the illustrations 

 (woodcuts). He was undoubtedly an enthusiastic entomologist ; it 

 is said he kept a painter for thirty years, whose sole employment was 

 delineating his specimens. Aldrovandus classified the insects in 

 two groups : 



1. Favica (terrestrial), 



2. Non-favica (aquatic), 



and formed orders according to the arrangement of the wings and 

 feet. Following Aldrovandus came Frenzius, who, in 161 2, classed 

 the insects in three great groups, which he named aerea, aquatica, 

 and terrea et reptantia. Some entomologists then seem to have paid 

 attention to certain Diptera. Redi, in 167 1, gave a good account of 

 several lice, parasitic upon birds, in his " Experimenta circa Gene- 

 rationem Insectorum," and soon after Sangallo wrote a paper on the 

 gnat ( Culex pipiens), illustrated by a plate. 



About this period the microscope began to come into use, and 

 many important physiological features in the insects were discovered, 

 notably the circulation of the blood. The use of the microscope 

 made great advances in the study of insects. The use, however, 

 of magnifying power was known before this, for numbers of years. 

 Amongst those who worked at the period on the microscopical 

 investigations of insects were Power, Hooke, and Hartsoeker. 

 Hooke, in 1665, published his " Micrographia," a work relating to 

 the microscopical structure of insects. 



We must now consider that great anatomical entomologist, Swam- 



