ORTHOCLADIUS, Spp., BREEDING IN THE SEA 193 



ORTHOCLADIUS, Spp., BREEDING IN THE SEA. 



By Richard Elmhirst, F.L.S., Superintendent of the Millport 

 Marine Biological Station. 



In a recent conversation Mr H. M. Fox (Ray Lankester 

 Investigator on Marine Insects at the Plymouth Laboratory) 

 suggested I should pubHsh a short account of observations 

 on marine breeding insects, particularly Chironomids, in the 

 Clyde area. 



Species I. Orthodadius sordidellus, Ztt. 



The larvae of this species occur frequently amongst 

 EnteromorpJia intestinalis and are generally found inside the 

 hollow fronds of the Enteromorpha. The habits of this 

 larva have been described by Mr T. H. Taylor in Trans. Ent. 

 Soc. Lond., 1904, pp. 521-3. 



The larvae occur in brackish and salt water and may be 

 reared in fresh, brackish, or salt water. The pupal stage 

 lasts about two days in summer but longer in cold weather. 

 Emergence of the imago takes a few minutes, and the imago 

 can fly within a similar time. Flies emerged 2ist August 

 1914, mated 11 A.M. 22nd, and the female deposited a mass 

 of ova by noon. The ova are about -24 mm. x-i2 mm., 

 rather irregularly placed in a tube within a thick gelatinous 

 covering generally curved and about 4 mm. x -5 mm. 



On summer evenings the flies occur in large flights about 

 the shore and are attracted by the lights of houses. Early 

 in August this year I collected a number of them associated 

 with Cnlicoides pulicaris ovi a wall near a gas bracket. I have 

 seen Ceratinostoma osfiorum, Hal., devouring an egg-laying 

 female O. sordidcllus. Bats feed along the shore when the 

 flies are abundant. 



Species II. Orthodadius, sp.? 



The larvae occur chiefly amongst PolysipJionia fastigiata 

 but also amongst Zostera and other weeds, at all tidal levels ; 

 they have also been taken in the surface tow-net, but these 

 95 AND 96 Y 



