MONOGRAPH OF THE LABOULBENIACE^E. 



245 



Total numbers of hosts in the different families of this order : — 



species, 3 

 1 

 2 

 1 



Nyctcribida; genera, 3 



Biopsida; " 1 



Drosophilidas " 1 



Muscidae " 1 



Total number of hosts belonging to the order Neuroptera 1 



A single family Termites genus, 1 ; species, 1 



Total number of hosts belonging to the order Arachnida 1 



A single family Gasmidae genus, 1 ; species, 1 



In comparing the species and genera represented by these hosts it is noticeable 

 that although the Carabidae exceed all other families as regards the number of genera 

 and of species, both of hosts and parasites, the number of genera by which they 

 are infested is comparatively small. Of the seventy-five species of Laboulbeniaceae 

 •which are found on members of this family, sixty-five belong to the single genus 

 Laboulbenia, while the remaining ten are distributed among but five genera, Dimero- 

 myces, Peyritschiella, Enarthromyces, and Rhachomyces. In the case of the Staphy- 

 linidae, however, which, next to the Carabidae, includes more hosts than any other 

 family, the proportions in this respect are quite different. For although the genus 

 Laboulbenia predominates to such a degree in the Carabidae and infests all of the 

 orders, and a majority of the families given in the above table ; among the fifty species 

 known on members of the Staphylinidae, but four belong to this genus, while the 

 remaining forty-two are distributed among no less than eighteen genera. The last 

 mentioned family is thus by far the most interesting in this connection, and its para- 

 sites abound in peculiar forms. 



It is further observable that the aquatic hosts, with the exception of the Gyrinidae, 

 the species of which swim on the surface of the water and carry their hosts at least 

 partly exposed to the air during much of their existence, are infested only by mem- 

 bers of the three genera Zodiomyces, Ceratomyces, Hvdraeomyces, and Chitonomyces, 

 of which the two first mentioned are the only representatives of the group of 

 " exogenae," producing their antherozoids exogenously. 



In general, it is true that among the Coleoptera infested a majority are either 

 riparian or aquatic in their habits; yet there are a number of forms that occur upon 

 insects which live away from the water and often inhabit rather dry situations. Of 

 these, Chilocorus is perhaps the best example ; while, outside the Coleoptera, the com- 

 mon house-fly affords a conspicuous instance of a host very subject to this parasitism, 

 yet far from riparian in its habit. Peyritsch notes the fact that, in his experience, 



