“…I also wish to thank Mike Silvers for his technical assistance throughout most of this thesis, my family for their patience and understanding, and to all those who have given me advice and aid throughout this time. dent from the many studies of the immune reactivity of invertebrates, especially insects, that cell-mediated reactions are the more prominant type of immune response, (Salt, 1955(Salt, , 1957(Salt, , 1959(Salt, , 1963a(Salt, , 1965(Salt, , 1970a(Salt, ,b, 1975Gupta and Sutherland, 1966;Mercer and Nicholas, 1967;Grimstone et al 1967;Peterson, 1968;Nappi, 1970aNappi, ,b, 1975aNappi, ,b, 1977bNappi, , 1981Nappi and Stoffolano, 1971;Scott, 1971a;Tripp, 1971;Misko, 1972;Poinar, 1975;Brennan, 1975;Brehelin et al, 1975;Lackie, 1975Lackie, , 1976Lackie, , 1979Lackie, , 1980Lackie, , 1981Lackie and Lackie, 1979;Schmit and Ratcliffe, 1977;Ratcliffe and Rowley, 1979;Ratcliffe and Gagen, 1976;Rowley andRatcliffe, 1979' 1981). However, against certain microbial agents, 1 insects and other invertebrates produce non-specific humoral factors, about which little is presently known (Chadwick, 19.67;Lackie, 1980;Jurenka et al, 1982;Rheins and Karp, 1982;Stynen et al, 1982;…”