Dear Arthur, Thank you for your interest, and my apologies for taking a while to respond. For fixing head lice at diffrent stages of oviposition, I used liquid "canned air" to stop them in their tracks, then tipped in an excess of hot alcoholic Bouin (or Dubosq Brasil as we entomologists called it). They were kept at 60 degrees for 1 hour, then transferred to alcohol for dehydration (Automatic embedder, 45 minute changes at 80%, 96% then 100% ethanol), clearing in toluene (2 x 45 min) and embedding in soft (mp 60 degrees) paraffin wax (2 x 45 min). This worked better than formaldehyde, gluteraldehyde, Susa, regular Bouin, or Carnoy for histological preservation. Fixing punctured insects or removed abdomens gave no benefit in preservation. I understand Picric acid fixatives preserve antigenicity at least as well as formalin. For dissecting out the reproductive system of head lice, I sprinkled them on a wax dish and used a soldering iron to melt in front of their head so they are trapped thorax deep in wax. By slicing off the tip of the abdomen with a mounted razor, all the innards can be squeezed out with fine angled forceps and fixed in formaldehyde. This got my dissection time down to a few seconds each and allowed me to do SEM of the internal organs. For making transparent whole mounts of fleas, the insects can be collected in 30% alcohol. I can't lay my hands on the exact protocol, but know it came from one of Mirriam Rothschild's old papers. The short cut was to put one pellet of KOH in an eppendorf with a ml of water. When dissolved, I added the fleas and kept it in a 60 degree incubator for I think 4 hours. The longer you leave them, the lighter they get. Embedding was done through alcohol, then oil of clove (try Xylene), then DPX. Good luck David Carter oQQQQQ@ Meridian Instruments Inc. (Purveyors of premium confocal laser scanning microscopes and workstations) 2310 Science Parkway Okemos Michigan 48864 USA Tel. 517 349-7200 Fax 517 349-5967 E-mail [log in to unmask]