OF WASHINGTON, VOLUME XI, 1909. 57 



probably more emerge during the month of June than at any 

 oilier time. From present indications the immature stages last 

 from ten to fifteen or even eighteen months, according to the 

 favorable or unfavorable conditions prevailing. The more 

 advanced larvae attain their full growth by the latter part of 

 the fall, sonic transforming to adults and remaining dormant 

 in their pupal cells throughout the winter, while others, quite 

 often of the same brood, overwinter in the larval form. The 

 pupal stage is very short, lasting but a few days. There is no 

 record of their overwintering in this stage. 



The other genus of this group infesting sound wood is 

 \ cina tod cs. Species of this genus make an entirely different 

 mine from the two previously mentioned ones. Instead of the 

 broad, flat, transverse mine these larvae excavate an oval or 

 nearly round mine, just large enough for the passage of the 

 larva ; it extends in a general parallel direction with the grain of 

 the wood, though winding in and out, and in some instances it is 

 found_ to have turned entirely around. The pupal cell is made 

 in the same parallel way. In this instance there is no exit hole 

 made by the larva, for it pupates close to the surface of the 

 wood and as the adult possesses large, strong mandibles it is 

 no great task for it to make its escape. This insect seems to 

 require damp conditions for its development, just opposite from 

 the condition which is normally preferred by species of Melasis 

 and Tharops. The galleries are usually discolored by a bluish 

 fungous growth, and near the surface or beginning the gallery 

 will often appear to be sap-stained, which would indicate that 

 the larva had been at work in its host before the sap had en- 

 tirely dried up. The life history of species of this genus has 

 not been satisfactorily worked out and the period of time 

 required for the development of the insect is not known. 

 Contrary in habit to the other two genera, this insect seems to 

 be partial to the coarse-grained woods of different species of 

 oak. A black oak sapling at Lynnhaven, Va., was found thick- 

 ly infested near the base by Nematodes atropos larvae, pupae, 

 and young imagos on June 15. Some of the beetles were then 

 beginning to emerge. Most of the mines appeared to be only 

 5 or (> inches in length ; they arc. however, very difficult to trace 

 to their source and many of them are doubtless longer. Species 

 of this genus are very rare, and even if abundant would pre- 

 .sumably be of little economic importance, as the small parallel 

 mines would be less injurious to timber than the broad trans- 

 verse mines of Melasis and Tharops. Although no known 

 larv;e of this family possess lep-s, as do those of the true Elat- 

 crids, there is in the larva of Ncinatodes atropos a chitinous 



