Immature Stages of Chironomidae
Detailed information on immature stages of Chironomidae is being acquired. However, Clausen (1940) noted species of the subfamily Tanypodinae subsist mainly on the larvae of other Chironomidae. Trissocladius equitans Claas., however, appears to be a true external parasite of the nymphs of a May fly, Rithrogena, and an account of its habits was provided by Claassen (1922). Larvae of various instars except the 1st are found on the mesothorax under the wing pads, and the head is embedded in the host tissues. A sheet of silk is spun over the body and is attached along its entire margin to the body of the host, so that no outside feeding can take place. The larva is thus closely confined to the host body. In its younger stages, the larva lies across the abdomen of the host, but later it assumes a V-shaped position (Fig. 157). Pupation occurs beneath the web, and the pupa works its way out from underneath this covering and ascends to the surface of the water just before adult emergence. Dactylocladius brevipalpus Galt was found to be parasitic on Mayfly nymphs of Rithogena and other genera in France. The larvae are found only beneath the wing pads, and the species is considered to be a true parasite rather than a commensal (Dorier 1938).
Please CLICK on picture to view details: