38 BULLETIN OF THE BUREAU OF FISHERIES. 



The behavior of the larvae belonging to this subfamily is quite similar for the members 

 of the group but very different from that of the larvae of the other subfamilies. The 

 Tanypinae differ from the Chironominae in the length and structure of the head and the 

 function and arrangement of the mouth parts. The anterior prolegs are less strongly 

 developed in Tanypus and are capable of being entirely retracted, so as not to give even 

 a protuberance on that part of the body. The posterior prolegs are more strongly 

 developed, are longer, and are furnished with claws of greater length than those of the 

 Chironominae. In other respects they differ less from the Chironominae in appearance 

 than in structure. They are not all nearly colorless, as Miall (1895) states, but there 

 are a few which are blood red in color. These differ in their behavior as will be explained 

 below. They also differ from all the aquatic members of the subfamily Ceratopogonince 

 in the possession of both anterior and posterior prolegs. 



In his study of this group the author has observed as many different species as he 

 could find, but his chief attention has been given to Tanypus carneus, T. hirtipennis, T. 

 monilis, and T. dyari, which have also been bred in the course of this work. 



Tanypus hirtipennis differs from the other species mentioned in having red blood 

 with which is correlated a burrowing habit. The presence of haemoglobin in the blood 

 seems to enable this species to live in a less well-aerated environment in the same way 

 that it does in the case of certain members of the subfamily Chironominae. They do 

 not build tubes as so many of the true bloodworms, however, but simply prowl around 

 pushing their inquisitive heads here and there among the organic debris at the bottom. 

 On this particular point Meinert (1886) states that the Tanypus larvae construct tubes 

 where they remain concealed. Dr. Johannsen tells the writer that in no case has he 

 observed them to behave in this manner. Since the salivary glands are much smaller 

 in proportion to the rest of the body, since the larvae live upon tube-dwelling larvae, 

 and since the pupae are active like those of Culex, it seems probable that they are only 

 found in tubes where they have gone in pursuit of their normal food. This also seems 

 most likely from the fact that the Tanypus larvae when disturbed flap themselves out of 

 the tube or debris where they are, as readily as otherwise, which is not the case with 

 the tube-building larvae. This species, except for its adaptation to a lower level where 

 it is more protected from bottom-crawling enemies as well as impeded in its locomotion, 

 differs but little from the surface-dwelling forms. 



Tanypus carneus is perhaps the best representative of a surface-dwelling member 

 of this subfamily. It is slim, has a head about three times as long as wide, and its 

 anterior proleg is long and slim and shows its double nature only toward the tip, where 

 it is divided into two rounded branches provided with a few rather delicate claws. This 

 proleg is capable of being completely withdrawn and thus adapts the larva to life among 

 filamentous algae where it seems most at home. The long posterior prolegs enable the 

 larvae to glide along snakelike through the filaments. When an enemy approaches, they 

 are able to withdraw by a backward flexing of these prolegs and the posterior end of 

 the body. Their behavior when sufficiently stimulated resembles that of the crayfish. 

 So rapid is their movement that whether their prolegs catch on any solid particles or 

 not they shoot backward far out of danger. When at rest on the debris beneath the 

 surface, the stimulation of their caudal setae causes them to give a little flip to their 

 bodies which brings their heads almost exactly at the point where their posterior ends 

 had been. This power to rapidly right about face, while especially characteristic of all 



